Knowledge (XXG)

Perfect number

Source 📝

2473: 1711: 5057: 2468:{\displaystyle {\begin{alignedat}{3}6&=2^{1}(2^{2}-1)&&=1+2+3,\\28&=2^{2}(2^{3}-1)&&=1+2+3+4+5+6+7\\&&&=1^{3}+3^{3}\\496&=2^{4}(2^{5}-1)&&=1+2+3+\cdots +29+30+31\\&&&=1^{3}+3^{3}+5^{3}+7^{3}\\8128&=2^{6}(2^{7}-1)&&=1+2+3+\cdots +125+126+127\\&&&=1^{3}+3^{3}+5^{3}+7^{3}+9^{3}+11^{3}+13^{3}+15^{3}\\33550336&=2^{12}(2^{13}-1)&&=1+2+3+\cdots +8189+8190+8191\\&&&=1^{3}+3^{3}+5^{3}+\cdots +123^{3}+125^{3}+127^{3}\end{alignedat}}} 38: 7743: 3272: 10004: 2907: 964: 1367:= 2, 3, 5, 7, 13, 17, 19, 31, 61, 89, 107, 127, 521, 607, 1279, 2203, 2281, 3217, 4253, 4423, 9689, 9941, 11213, 19937, 21701, 23209, 44497, 86243, 110503, 132049, 216091, 756839, 859433, 1257787, 1398269, 2976221, 3021377, 6972593, 13466917, 20996011, 24036583, 25964951, 30402457, 32582657, 37156667, 42643801, 43112609 and 57885161 (sequence 461:(1194–1252) mentioned the next three perfect numbers (33,550,336; 8,589,869,056; and 137,438,691,328) and listed a few more which are now known to be incorrect. The first known European mention of the fifth perfect number is a manuscript written between 1456 and 1461 by an unknown mathematician. In 1588, the Italian mathematician 5562:, Chapter 16, he says of perfect numbers, "There is a method of producing them, neat and unfailing, which neither passes by any of the perfect numbers nor fails to differentiate any of those that are not such, which is carried out in the following way." He then goes on to explain a procedure which is equivalent to finding a 4729: 664: 3267:{\displaystyle {\begin{array}{rcl}6_{10}=&2^{2}+2^{1}&=110_{2}\\28_{10}=&2^{4}+2^{3}+2^{2}&=11100_{2}\\496_{10}=&2^{8}+2^{7}+2^{6}+2^{5}+2^{4}&=111110000_{2}\\8128_{10}=&\!\!2^{12}+2^{11}+2^{10}+2^{9}+2^{8}+2^{7}+2^{6}\!\!&=1111111000000_{2}\end{array}}} 5259:
is a natural number that is equal to the sum of all or some of its proper divisors. A semiperfect number that is equal to the sum of all its proper divisors is a perfect number. Most abundant numbers are also semiperfect; abundant numbers which are not semiperfect are called
4462:
All even perfect numbers have a very precise form; odd perfect numbers either do not exist or are rare. There are a number of results on perfect numbers that are actually quite easy to prove but nevertheless superficially impressive; some of them also come under
4556: 4074: 2632: 3881: 959:{\displaystyle {\begin{aligned}p=2&:\quad 2^{1}(2^{2}-1)=2\times 3=6\\p=3&:\quad 2^{2}(2^{3}-1)=4\times 7=28\\p=5&:\quad 2^{4}(2^{5}-1)=16\times 31=496\\p=7&:\quad 2^{6}(2^{7}-1)=64\times 127=8128.\end{aligned}}} 3319:
stated that Euclid's rule gives all perfect numbers, thus implying that no odd perfect number exists, but Euler himself stated: "Whether ... there are any odd perfect numbers is a most difficult question". More recently,
4453:... a prolonged meditation on the subject has satisfied me that the existence of any one such —its escape, so to say, from the complex web of conditions which hem it in on all sides—would be little short of a miracle. 3967: 3606: 61:, that is, divisors excluding the number itself. For instance, 6 has proper divisors 1, 2 and 3, and 1 + 2 + 3 = 6, so 6 is a perfect number. The next perfect number is 28, since 1 + 2 + 4 + 7 + 14 = 28. 445:
in his first-century book "On the creation" mentions perfect numbers, claiming that the world was created in 6 days and the moon orbits in 28 days because 6 and 28 are perfect. Philo is followed by
4269: 669: 1716: 441:
itself has to be prime. He also says (wrongly) that the perfect numbers end in 6 or 8 alternately. (The first 5 perfect numbers end with digits 6, 8, 6, 8, 6; but the sixth also ends in 6.)
1231:(Alhazen) circa AD 1000 was unwilling to go that far, declaring instead (also without proof) that the formula yielded only every even perfect number. It was not until the 18th century that 4836: 1385:= 74207281, 77232917, and 82589933. Although it is still possible there may be others within this range, initial but exhaustive tests by GIMPS have revealed no other perfect numbers for 3766: 2692:
It follows that by adding the digits of any even perfect number (except 6), then adding the digits of the resulting number, and repeating this process until a single digit (called the
4437: 7035: 465:
identified the sixth (8,589,869,056) and the seventh (137,438,691,328) perfect numbers, and also proved that every perfect number obtained from Euclid's rule ends with a 6 or an 8.
4724:{\displaystyle {\frac {1}{6}}+{\frac {1}{3}}+{\frac {1}{2}}+{\frac {1}{1}}={\frac {1}{6}}+{\frac {2}{6}}+{\frac {3}{6}}+{\frac {6}{6}}={\frac {1+2+3+6}{6}}={\frac {2\cdot 6}{6}}=2} 2480: 1614: 1704: 1658: 457:(Book XI, Chapter 30) in the early 5th century AD, repeating the claim that God created the world in 6 days because 6 is the smallest perfect number. The Egyptian mathematician 8106: 4544: 4372: 3687: 2889: 651: 130: 4920: 2824: 2761: 1457: 1358: 1288: 1192: 551: 402: 3974: 5246: 5027: 87:, so a perfect number is one that is equal to its aliquot sum. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors; in symbols, 6848: 4990: 3492: 3416: 3452: 453:, who adds the observation that there are only four perfect numbers that are less than 10,000. (Commentary on Genesis 1. 14–19). St Augustine defines perfect numbers in 157: 3332:, and it has been conjectured as well that there are no odd harmonic divisor numbers other than 1. Many of the properties proved about odd perfect numbers also apply to 337:
In about 300 BC Euclid showed that if 2 âˆ’ 1 is prime then 2(2 âˆ’ 1) is perfect. The first four perfect numbers were the only ones known to early
1496: 5436: 236: 5353: 4956: 1566: 1533: 1225: 1126: 1081: 1044: 999: 584: 435: 292: 1294:
between even perfect numbers and Mersenne primes; each Mersenne prime generates one even perfect number, and vice versa. This result is often referred to as the
312: 256: 10038: 5283: 3772: 7686: 5446: 1374: 8099: 3309: 1394: 489: 5791: 5745: 5036:
Every even perfect number ends in 6 or 28, base ten; and, with the only exception of 6, ends in 1 in base 9. Therefore, in particular the
3888: 8906: 8092: 5923: 1389:
below 109332539. As of December 2018, 51 Mersenne primes are known, and therefore 51 even perfect numbers (the largest of which is
3522: 8901: 8916: 8896: 3316: 7732: 7538: 7382: 7209: 5721: 5694: 5647: 5558: 9609: 9189: 7929: 7742: 5113: 6244: 6147: 3336:, and Pace Nielsen has suggested that sufficient study of those numbers may lead to a proof that no odd perfect numbers exist. 8911: 5767: 9695: 4209: 7679: 7573: 4867:. There are only three types of non-trapezoidal numbers: even perfect numbers, powers of two, and the numbers of the form 9011: 9361: 8680: 8473: 2660:(after subtracting 1 from the perfect number and dividing the result by 9) ending in 3 or 5, the sequence starting with 9396: 9366: 9041: 9031: 7883: 6007:
KĂŒhnel, Ullrich (1950). "VerschĂ€rfung der notwendigen Bedingungen fĂŒr die Existenz von ungeraden vollkommenen Zahlen".
9537: 8951: 8685: 8665: 7568: 5628: 5196: 4468: 9227: 7638: 9391: 10033: 9486: 9109: 8866: 8675: 8657: 8551: 8541: 8531: 7919: 7476: 6749: 6543: 5962: 5109: 9371: 5906: 10028: 9614: 9159: 8780: 8566: 8561: 8556: 8546: 8523: 7904: 7131:
The Collected Mathematical Papers of James Joseph Sylvester p. 590, tr. from "Sur les nombres dits de Hamilton",
5192: 5078: 4737: 1617: 3700: 1295: 474: 323: 10048: 10043: 8599: 7672: 5796: 5590: 5056: 160: 8856: 7446:
Steuerwald, R. "VerschĂ€rfung einer notwendigen Bedingung fĂŒr die Existenz einer ungeraden vollkommenen Zahl".
7377:. Chapman & Hall/CRC Pure and Applied Mathematics. Vol. 201. CRC Press. Problem 7.4.11, p. 428. 4851: 4377: 329:
It is not known whether there are any odd perfect numbers, nor whether infinitely many perfect numbers exist.
5532: 9725: 9690: 9476: 9386: 9260: 9235: 9144: 9134: 8746: 8728: 8648: 8058: 7924: 7848: 7000: 6846:(1950). "Satze uber Kreisteilungspolynome und ihre Anwendungen auf einige zahlentheoretisehe Probleme. II". 5303: 5288: 5100: 3329: 37: 1575: 9985: 9255: 9129: 8760: 8536: 8316: 8243: 7909: 7868: 6197:
Zelinsky, Joshua (July 2019). "Upper bounds on the second largest prime factor of an odd perfect number".
5576: 5298: 5087: 4494: 4446: 1663: 5637: 3499:
has at least 101 prime factors and at least 10 distinct prime factors. If 3 is not one of the factors of
3315:
It is unknown whether any odd perfect numbers exist, though various results have been obtained. In 1496,
9240: 9094: 9021: 8176: 7838: 7707: 4069:{\displaystyle {\frac {1}{q}}+{\frac {1}{p_{1}}}+{\frac {1}{p_{2}}}+\cdots +{\frac {1}{p_{k}}}<\ln 2} 1623: 31: 9949: 9589: 5184:. A positive integer such that every smaller positive integer is a sum of distinct divisors of it is a 4504: 4326: 3654: 2836: 598: 90: 7410: 5875: 5160:
gives various other kinds of numbers. Numbers where the sum is less than the number itself are called
4958:
with a power of two in a similar way to the construction of even perfect numbers from Mersenne primes.
4870: 2774: 2711: 1407: 1308: 1238: 1142: 501: 352: 9882: 9776: 9740: 9481: 9204: 9184: 9001: 8670: 8458: 8430: 8012: 7914: 7405: 6396: 6259: 6162: 6084: 5375: 5096: 588: 167: 7618: 7586: 7563: 6043: 5786: 5227: 4999: 345:
noted 8128 as early as around AD 100. In modern language, Nicomachus states without proof that
9604: 9468: 9463: 9431: 9194: 9169: 9164: 9139: 9069: 9065: 8996: 8886: 8718: 8514: 8483: 8073: 8068: 7863: 7858: 7843: 7782: 7044: 6911: 5782: 5293: 5273: 5044: 442: 10003: 4968: 3460: 3384: 10007: 9761: 9756: 9670: 9644: 9542: 9521: 9293: 9174: 9124: 9046: 9016: 8956: 8723: 8703: 8634: 8347: 7997: 7992: 7953: 7873: 7853: 7495: 7434: 7320: 7285: 7250: 7242: 7114: 7088: 6881: 6717: 6588: 6412: 6386: 6224: 6206: 6024: 5633: 5358: 5256: 4860: 4148: 4144: 4128: 4112: 3641: 3423: 3325: 2696:) is obtained, always produces the number 1. For example, the digital root of 8128 is 1, because 454: 135: 8891: 6843: 1462: 9901: 9846: 9700: 9675: 9649: 9426: 9104: 9099: 9026: 9006: 8991: 8713: 8695: 8614: 8604: 8589: 8367: 8352: 8033: 7973: 7593: 7534: 7530: 7506:
Riele, H.J.J. "Perfect Numbers and Aliquot Sequences" in H.W. Lenstra and R. Tijdeman (eds.):
7378: 7372: 7205: 7106: 7053: 6969: 6920: 6865: 6817: 6768: 6701: 5981: 5831: 5761: 5717: 5711: 5690: 5684: 5643: 5563: 5405: 5030: 4864: 3277: 2627:{\displaystyle T_{2^{p}-1}=1+{\frac {(2^{p}-2)\times (2^{p}+1)}{2}}=1+9\times T_{(2^{p}-2)/3}} 1499: 450: 338: 198: 7355: 7199: 5667: 5325: 4928: 1538: 1505: 1197: 1098: 1053: 1016: 971: 556: 407: 264: 9937: 9730: 9316: 9288: 9278: 9270: 9154: 9119: 9114: 9081: 8775: 8738: 8629: 8624: 8619: 8609: 8581: 8468: 8420: 8415: 8372: 8311: 8063: 8038: 7958: 7944: 7878: 7762: 7722: 7544: 7522: 7485: 7426: 7312: 7277: 7234: 7177: 7098: 6959: 6857: 6807: 6758: 6693: 6552: 6486: 6404: 6343: 6267: 6216: 6170: 6128: 6092: 6016: 5989: 5971: 5859: 5516: 5249: 5221: 5185: 5161: 5149: 5140: 3333: 3284: 1569: 54: 7065: 6981: 6932: 6877: 6829: 6780: 6713: 9913: 9802: 9735: 9661: 9584: 9558: 9376: 9089: 8946: 8881: 8851: 8841: 8836: 8502: 8410: 8357: 8201: 8141: 8048: 8043: 7968: 7962: 7899: 7797: 7787: 7717: 7548: 7061: 6977: 6928: 6873: 6825: 6776: 6709: 5993: 5910: 5181: 5177: 5165: 5069: 6684:
McDaniel, Wayne L. (1970). "The non-existence of odd perfect numbers of a certain form".
4486:
28 is also the only even perfect number that is a sum of two positive cubes of integers (
7079:
Yamada, Tomohiro (2019). "A new upper bound for odd perfect numbers of a special form".
6400: 6263: 6166: 6088: 6069: 4863:; that is, they cannot be represented as the difference of two positive non-consecutive 3328:
suggesting that indeed no odd perfect number should exist. All perfect numbers are also
9918: 9786: 9771: 9635: 9599: 9574: 9450: 9421: 9406: 9179: 8876: 8831: 8708: 8306: 8301: 8296: 8268: 8253: 8166: 8151: 8129: 8116: 8053: 8007: 7817: 7807: 7777: 5499: 5278: 5224:
associated with a perfect number is a constant sequence. All perfect numbers are also
5157: 4843:
The number of divisors of a perfect number (whether even or odd) must be even, because
4464: 3321: 1232: 1228: 1006: 1002: 462: 319: 315: 297: 241: 7664: 6964: 6947: 5370:, and both 23 and 89 yield a remainder of 1 when divided by 22. Furthermore, whenever 2912: 10022: 9841: 9825: 9766: 9720: 9416: 9401: 9311: 9036: 8594: 8463: 8425: 8382: 8263: 8248: 8238: 8196: 8186: 8161: 8002: 7802: 7792: 7772: 7523: 7438: 7351: 7324: 7289: 7254: 7118: 6885: 6721: 6028: 5855: 5663: 5512: 5060: 3876:{\displaystyle \alpha +2e_{1}+2e_{2}+2e_{3}+\cdots +2e_{k}\geq {\frac {99k-224}{37}}} 1010: 77: 46: 7630: 6763: 6741: 6557: 6538: 6348: 6228: 6119:
Konyagin, Sergei; Acquaah, Peter (2012). "On Prime Factors of Odd Perfect Numbers".
5976: 9877: 9866: 9781: 9619: 9594: 9511: 9411: 9381: 9356: 9340: 9245: 9212: 8961: 8935: 8846: 8785: 8362: 8258: 8191: 8171: 8146: 8017: 7934: 7812: 7757: 7727: 7596: 6996: 6416: 5834: 5261: 5122: 5037: 4923: 2693: 1398: 1305:
distributed computing project has shown that the first 48 even perfect numbers are
658: 73: 7466:
Nankar, M.L.: "History of perfect numbers," Ganita Bharati 1, no. 1–2 (1979), 7–8.
6408: 6295: 6272: 6175: 6097: 5500:"A proof that all even perfect numbers are a power of two times a Mersenne prime" 5176:. A pair of numbers which are the sum of each other's proper divisors are called 9836: 9711: 9516: 8980: 8871: 8826: 8821: 8571: 8478: 8377: 8206: 8181: 8156: 7646: 6903: 6574:"On inequalities involving counts of the prime factors of an odd perfect number" 6573: 6441: 6148:"The second largest prime divisor of an odd perfect number exceeds ten thousand" 259: 84: 69: 6328: 1381:
Three higher perfect numbers have also been discovered, namely those for which
17: 9973: 9954: 9250: 8861: 7650: 6997:"Some results concerning the non-existence of odd perfect numbers of the form 6861: 6812: 6795: 6491: 6474: 6371: 6245:"The third largest prime divisor of an odd perfect number exceeds one hundred" 6220: 6132: 5740: 5173: 1132: 458: 342: 65: 8084: 7430: 7303:
Kanold, HJ (1956). "Eine Bemerkung šuber die Menge der vollkommenen zahlen".
7110: 7057: 6973: 6924: 6869: 6821: 6772: 6705: 5985: 1091:
is not a prime number. In fact, Mersenne primes are very rare: of the primes
9579: 9506: 9498: 9303: 9217: 8335: 7767: 7621:
A projected distributed computing project to search for odd perfect numbers.
7601: 6507: 5839: 1291: 322:
proved that all even perfect numbers are of this form. This is known as the
7225:
Jones, Chris; Lord, Nick (1999). "Characterising non-trapezoidal numbers".
7102: 6616: 5575:
Commentary on the Gospel of John 28.1.1–4, with further references in the
4175:
must be smaller than an effectively computable constant depending only on
9680: 7417:
Kanold, H.-J. (1941). "Untersuchungen ĂŒber ungerade vollkommene Zahlen".
5954: 5592:
The Reception of Philonic Arithmological Exegesis in Didymus the Blind's
595:
For example, the first four perfect numbers are generated by the formula
4501:
must add up to 2 (to get this, take the definition of a perfect number,
1401:
perfect numbers, nor whether there are infinitely many Mersenne primes.
9685: 9344: 7712: 7499: 7316: 7281: 7246: 6697: 6020: 5902: 3298: 478: 58: 7182: 7165: 6735: 6733: 6731: 6391: 5617:
The Development of Arabic Mathematics: Between Arithmetic and Algebra
3420:
The second largest prime factor is greater than 10, and is less than
495: 446: 192: 7490: 7471: 7268:
Hornfeck, B (1955). "Zur Dichte der Menge der vollkommenen zahlen".
7238: 4198:) =  (1, ..., 1, 2, ..., 2) with 7413:
for a translation and discussion of this proposition and its proof.
7093: 6593: 6211: 3962:{\displaystyle qp_{1}p_{2}p_{3}\cdots p_{k}<2N^{\frac {17}{26}}} 7983: 6294:
Bibby, Sean; Vyncke, Pieter; Zelinsky, Joshua (23 November 2021).
5055: 4850:
From these two results it follows that every perfect number is an
3457:
The third largest prime factor is greater than 100, and less than
1302: 36: 7610: 5603:
Society of Biblical Literature National Meeting, Atlanta, Georgia
4082:
Furthermore, several minor results are known about the exponents
3601:{\displaystyle N=q^{\alpha }p_{1}^{2e_{1}}\cdots p_{k}^{2e_{k}},} 5716:. Washington: Mathematical Association of America. p. 132. 5686:
Wonders of Numbers: Adventures in Mathematics, Mind, and Meaning
5619:(Dordrecht: Kluwer Academic Publishers, 1994), pp. 328–329. 9971: 9935: 9899: 9863: 9823: 9448: 9337: 9063: 8978: 8933: 8810: 8500: 8447: 8399: 8333: 8285: 8223: 8127: 8088: 7668: 6442:"On the Total Number of Prime Factors of an Odd Perfect Number" 6372:"Odd perfect numbers have at least nine distinct prime factors" 7581: 7374:
Number Theory: An Introduction to Pure and Applied Mathematics
6948:"A new result concerning the structure of odd perfect numbers" 6329:"Odd perfect numbers, Diophantine equations, and upper bounds" 5924:"Mathematicians Open a New Front on an Ancient Number Problem" 7360:. Washington: Carnegie Institution of Washington. p. 25. 6296:"On the Third Largest Prime Divisor of an Odd Perfect Number" 5672:. Washington: Carnegie Institution of Washington. p. 10. 174: 7624: 6897: 6895: 5864:. Washington: Carnegie Institution of Washington. p. 6. 5521:. Washington: Carnegie Institution of Washington. p. 4. 5233: 1572:. Furthermore, each even perfect number except for 6 is the 7613: 6904:"Extensions of some results concerning odd perfect numbers" 6740:
Fletcher, S. Adam; Nielsen, Pace P.; Ochem, Pascal (2012).
5809: 5475: 5450: 2891:
every even perfect number is represented in binary form as
1369: 1290:
will yield all the even perfect numbers. Thus, there is a
6539:"On the number of prime factors of an odd perfect number" 5713:
Mathematical Treks: From Surreal Numbers to Magic Circles
4290:) ≠ (1, ..., 1, 3), (1, ..., 1, 5), (1, ..., 1, 6). 41:
Illustration of the perfect number status of the number 6
7472:"A Lower Bound for the set of odd Perfect Prime Numbers" 6800:
Journal of the Australian Mathematical Society, Series A
6665:
Suryanarayana, D. (1963). "On Odd Perfect Numbers II".
5948: 5946: 5944: 1227:
is prime (though he stated this somewhat differently),
6070:"Odd perfect numbers have a prime factor exceeding 10" 4264:{\displaystyle (t-1)/4\leq u\leq 2t+{\sqrt {\alpha }}} 1580: 1502:(and hence equal to the sum of the integers from 1 to 1050:
itself be prime. However, not all numbers of the form
7204:, John Wiley & Sons, Section 2.3, Exercise 2(6), 7003: 5408: 5328: 5230: 5002: 4971: 4931: 4873: 4740: 4559: 4507: 4380: 4329: 4212: 3977: 3891: 3775: 3703: 3657: 3525: 3463: 3426: 3387: 2910: 2839: 2777: 2714: 2483: 1714: 1666: 1626: 1578: 1541: 1508: 1465: 1410: 1311: 1241: 1200: 1145: 1101: 1056: 1019: 974: 667: 601: 559: 504: 410: 355: 300: 267: 244: 201: 138: 93: 83:
The sum of proper divisors of a number is called its
7515:
Prime Numbers and Computer Methods for Factorisation
6475:"Improved upper bounds for odd multiperfect numbers" 9795: 9749: 9709: 9660: 9634: 9567: 9551: 9530: 9497: 9462: 9302: 9269: 9226: 9203: 9080: 8768: 8759: 8737: 8694: 8656: 8647: 8580: 8522: 8513: 8026: 7982: 7943: 7892: 7826: 7750: 7700: 7201:
Computational Number Theory and Modern Cryptography
6796:"On the largest component of an odd perfect number" 5735: 5733: 7145:Makowski, A. (1962). "Remark on perfect numbers". 7029: 5430: 5347: 5240: 5021: 4984: 4950: 4914: 4830: 4723: 4538: 4431: 4366: 4263: 4068: 3961: 3875: 3760: 3681: 3600: 3486: 3446: 3410: 3266: 2883: 2818: 2755: 2626: 2467: 1698: 1652: 1608: 1560: 1527: 1490: 1451: 1352: 1282: 1219: 1186: 1120: 1075: 1038: 993: 958: 645: 578: 545: 429: 396: 306: 286: 250: 230: 166:This definition is ancient, appearing as early as 151: 124: 3244: 3243: 3154: 3153: 6952:Proceedings of the American Mathematical Society 6667:Proceedings of the American Mathematical Society 6646:Cohen, Graeme (1978). "On odd perfect numbers". 6435: 6433: 5689:. Oxford: Oxford University Press. p. 360. 2477:Even perfect numbers (except 6) are of the form 57:that is equal to the sum of its positive proper 7419:Journal fĂŒr die Reine und Angewandte Mathematik 7166:"On a remark of Makowski about perfect numbers" 6849:Journal fĂŒr die reine und angewandte Mathematik 6479:Bulletin of the Australian Mathematical Society 5040:of every even perfect number other than 6 is 1. 4451: 27:Integer equal to the sum of its proper divisors 7510:, Vol. 154, Amsterdam, 1982, pp. 141–157. 7233:(497). The Mathematical Association: 262–263. 8100: 7680: 6995:McDaniel, Wayne L.; Hagis, Peter Jr. (1975). 6946:Hagis, Peter Jr.; McDaniel, Wayne L. (1972). 4167:+1 have a prime factor in a given finite set 195:also proved a formation rule (IX.36) whereby 8: 7614:sequence A000396 (Perfect numbers) 5284:List of Mersenne primes and perfect numbers 5164:, and where it is greater than the number, 4831:{\displaystyle 1/28+1/14+1/7+1/4+1/2+1/1=2} 9968: 9932: 9896: 9860: 9820: 9494: 9459: 9445: 9334: 9077: 9060: 8975: 8930: 8807: 8765: 8653: 8519: 8510: 8497: 8444: 8401:Possessing a specific set of other numbers 8396: 8330: 8282: 8220: 8124: 8107: 8093: 8085: 7687: 7673: 7665: 7521:SĂĄndor, Jozsef; Crstici, Borislav (2004). 5443:= 11, 23, 83, 131, 179, 191, 239, 251, ... 5180:, and larger cycles of numbers are called 3761:{\displaystyle N<2^{(4^{k+1}-2^{k+1})}} 3691:At least one of the prime powers dividing 486:Are there infinitely many perfect numbers? 7489: 7181: 7092: 7018: 7008: 7002: 6963: 6811: 6762: 6592: 6556: 6490: 6390: 6347: 6271: 6210: 6174: 6096: 5975: 5955:"Odd perfect numbers are greater than 10" 5413: 5407: 5333: 5327: 5232: 5231: 5229: 5009: 5001: 4975: 4970: 4936: 4930: 4897: 4878: 4872: 4814: 4800: 4786: 4772: 4758: 4744: 4739: 4697: 4664: 4651: 4638: 4625: 4612: 4599: 4586: 4573: 4560: 4558: 4512: 4506: 4475:The only even perfect number of the form 4404: 4396: 4391: 4379: 4343: 4328: 4254: 4228: 4211: 4046: 4037: 4020: 4011: 4000: 3991: 3978: 3976: 3948: 3932: 3919: 3909: 3899: 3890: 3852: 3843: 3821: 3805: 3789: 3774: 3741: 3722: 3714: 3702: 3658: 3656: 3587: 3579: 3574: 3559: 3551: 3546: 3536: 3524: 3474: 3464: 3462: 3437: 3427: 3425: 3398: 3388: 3386: 3254: 3237: 3224: 3211: 3198: 3185: 3172: 3159: 3142: 3128: 3113: 3100: 3087: 3074: 3061: 3046: 3032: 3017: 3004: 2991: 2976: 2962: 2947: 2934: 2919: 2911: 2909: 2863: 2844: 2838: 2801: 2782: 2776: 2738: 2719: 2713: 2614: 2599: 2591: 2551: 2526: 2516: 2493: 2488: 2482: 2455: 2442: 2429: 2410: 2397: 2384: 2306: 2293: 2269: 2256: 2243: 2230: 2217: 2204: 2191: 2178: 2100: 2087: 2063: 2050: 2037: 2024: 1946: 1933: 1909: 1896: 1818: 1805: 1746: 1733: 1715: 1713: 1671: 1665: 1631: 1625: 1587: 1579: 1577: 1546: 1540: 1513: 1507: 1473: 1464: 1434: 1415: 1409: 1335: 1316: 1310: 1265: 1246: 1240: 1205: 1199: 1169: 1150: 1144: 1106: 1100: 1061: 1055: 1024: 1018: 979: 973: 919: 906: 848: 835: 777: 764: 706: 693: 668: 666: 625: 606: 600: 564: 558: 528: 509: 503: 415: 409: 379: 360: 354: 299: 272: 266: 243: 220: 200: 143: 137: 98: 92: 7357:History of the Theory of Numbers, Vol. I 6508:"An upper bound for odd perfect numbers" 5876:"The oldest open problem in mathematics" 5861:History of the Theory of Numbers, Vol. I 5669:History of the Theory of Numbers, Vol. I 5518:History of the Theory of Numbers, Vol. I 4961:The number of perfect numbers less than 4487: 4480: 4432:{\displaystyle N<2^{4^{2e^{2}+8e+3}}} 2826:for odd integer (not necessarily prime) 7529:. Dordrecht: Kluwer Academic. pp.  7133:Compte Rendu de l'Association Française 6742:"Sieve methods for odd perfect numbers" 6615:Pomerance, Carl; Luca, Florian (2010). 5792:MacTutor History of Mathematics Archive 5467: 5315: 4321:cannot be 3, 5, 24, 6, 8, 11, 14 or 18. 3507:has at least 12 distinct prime factors. 3343:must satisfy the following conditions: 3310:(more unsolved problems in mathematics) 1660:odd cubes (odd cubes up to the cube of 490:(more unsolved problems in mathematics) 7582:Perfect, amicable and sociable numbers 7508:Computational Methods in Number Theory 7030:{\displaystyle p^{\alpha }M^{2\beta }} 6902:Cohen, G. L.; Williams, R. J. (1985). 6199:International Journal of Number Theory 6121:International Journal of Number Theory 6044:"On the Form of an Odd Perfect Number" 5759: 4151:5), then the smallest prime factor of 2708:. This works with all perfect numbers 2636:with each resulting triangular number 437:is prime. He seems to be unaware that 5191:By definition, a perfect number is a 3288: 1620:and is equal to the sum of the first 1609:{\displaystyle {\tfrac {2^{p}+1}{3}}} 1005:, after the seventeenth-century monk 7: 7625:Great Internet Mersenne Prime Search 7587:Perfect numbers – History and Theory 6617:"On the radical of a perfect number" 6572:Graeme Clayton, Cody Hansen (2023). 6537:Ochem, Pascal; Rao, MichaĂ«l (2014). 6473:Chen, Yong-Gao; Tang, Cui-E (2014). 5953:Ochem, Pascal; Rao, MichaĂ«l (2012). 5746:Great Internet Mersenne Prime Search 4996:> 0 is a constant. In fact it is 4497:of the divisors of a perfect number 4171:, then the smallest prime factor of 3283:Every even perfect number is also a 3276:Thus every even perfect number is a 1699:{\displaystyle 2^{\frac {p+1}{2}}-1} 7695:Divisibility-based sets of integers 5394:is congruent to 1 or 7 mod 8, then 553:is an even perfect number whenever 238:is an even perfect number whenever 64:The first four perfect numbers are 10039:Unsolved problems in number theory 6440:Zelinsky, Joshua (3 August 2021). 5922:Nadis, Steve (10 September 2020). 3306:Are there any odd perfect numbers? 1653:{\displaystyle 2^{\frac {p-1}{2}}} 1459:, each even perfect number is the 1046:to be prime, it is necessary that 25: 7733:Fundamental theorem of arithmetic 6965:10.1090/S0002-9939-1972-0292740-5 5787:"Abu Ali al-Hasan ibn al-Haytham" 5639:History of Mathematics: Volume II 4859:The even perfect numbers are not 4539:{\displaystyle \sigma _{1}(n)=2n} 4367:{\displaystyle k\leq 2e^{2}+8e+2} 3682:{\displaystyle {\frac {k-1}{2}}.} 3381:is greater than 10 and less than 2884:{\displaystyle 2^{p-1}(2^{p}-1),} 1139:perfect numbers were of the form 646:{\displaystyle 2^{p-1}(2^{p}-1),} 125:{\displaystyle \sigma _{1}(n)=2n} 10002: 9610:Perfect digit-to-digit invariant 7741: 4915:{\displaystyle 2^{n-1}(2^{n}+1)} 3634:are distinct odd primes (Euler). 2819:{\displaystyle 2^{m-1}(2^{m}-1)} 2756:{\displaystyle 2^{p-1}(2^{p}-1)} 1452:{\displaystyle 2^{p-1}(2^{p}-1)} 1353:{\displaystyle 2^{p-1}(2^{p}-1)} 1283:{\displaystyle 2^{p-1}(2^{p}-1)} 1187:{\displaystyle 2^{n-1}(2^{n}-1)} 1135:had stated (without proof) that 546:{\displaystyle 2^{p-1}(2^{p}-1)} 397:{\displaystyle 2^{n-1}(2^{n}-1)} 7409:, Book IX, Proposition 36. See 6764:10.1090/S0025-5718-2011-02576-7 6621:New York Journal of Mathematics 6558:10.1090/S0025-5718-2013-02776-7 6349:10.1090/S0025-5718-2015-02941-X 6051:Australian Mathematical Gazette 5977:10.1090/S0025-5718-2012-02563-4 5642:. New York: Dover. p. 21. 3301:Unsolved problem in mathematics 1393:with 49,724,095 digits). It is 901: 830: 759: 688: 481:Unsolved problem in mathematics 7341:Texeira J. VIII (1886), 11–16. 7135:(Toulouse, 1887), pp. 164–168. 5241:{\displaystyle {\mathcal {S}}} 5022:{\displaystyle o({\sqrt {n}})} 5016: 5006: 4909: 4890: 4524: 4518: 4225: 4213: 3753: 3715: 2875: 2856: 2813: 2794: 2750: 2731: 2611: 2592: 2563: 2544: 2538: 2519: 2318: 2299: 2112: 2093: 1958: 1939: 1830: 1811: 1758: 1739: 1485: 1466: 1446: 1427: 1347: 1328: 1277: 1258: 1181: 1162: 1128:is prime for only 48 of them. 931: 912: 860: 841: 789: 770: 718: 699: 637: 618: 540: 521: 391: 372: 349:perfect number is of the form 217: 205: 110: 104: 1: 8449:Expressible via specific sums 7339:Note sur les nombres parfaits 6409:10.1090/S0025-5718-07-01990-4 6273:10.1090/S0025-5718-99-01127-8 6176:10.1090/S0025-5718-99-01126-6 6098:10.1090/S0025-5718-08-02050-9 5168:. These terms, together with 3647:The smallest prime factor of 7525:Handbook of number theory II 4985:{\displaystyle c{\sqrt {n}}} 4847:cannot be a perfect square. 3487:{\displaystyle {\sqrt{2N}}.} 3411:{\displaystyle {\sqrt{3N}}.} 3377:The largest prime factor of 1301:An exhaustive search by the 173:(VII.22) where it is called 9538:Multiplicative digital root 7569:Encyclopedia of Mathematics 5629:Bayerische Staatsbibliothek 5537:www-groups.dcs.st-and.ac.uk 5197:restricted divisor function 4922:formed as the product of a 4546:, and divide both sides by 4469:strong law of small numbers 4155:must lie between 10 and 10. 3447:{\displaystyle {\sqrt{2N}}} 1404:As well as having the form 152:{\displaystyle \sigma _{1}} 10065: 7477:Mathematics of Computation 7164:Gallardo, Luis H. (2010). 6750:Mathematics of Computation 6544:Mathematics of Computation 6379:Mathematics of Computation 6336:Mathematics of Computation 6252:Mathematics of Computation 6155:Mathematics of Computation 6077:Mathematics of Computation 5963:Mathematics of Computation 5766:: CS1 maint: url-status ( 5589:Rogers, Justin M. (2015). 5566:based on a Mersenne prime. 5559:Introduction to Arithmetic 968:Prime numbers of the form 472: 175: 29: 9998: 9981: 9967: 9945: 9931: 9909: 9895: 9873: 9859: 9832: 9819: 9615:Perfect digital invariant 9458: 9444: 9352: 9333: 9190:Superior highly composite 9076: 9059: 8987: 8974: 8942: 8929: 8817: 8806: 8509: 8496: 8454: 8443: 8406: 8395: 8343: 8329: 8292: 8281: 8234: 8219: 8137: 8123: 7930:Superior highly composite 7739: 6862:10.1515/crll.1950.188.129 6813:10.1017/S1446788700028251 6506:Nielsen, Pace P. (2003). 6492:10.1017/S0004972713000488 6370:Nielsen, Pace P. (2007). 6327:Nielsen, Pace P. (2015). 6221:10.1142/S1793042119500659 6133:10.1142/S1793042112500935 6068:Goto, T; Ohno, Y (2008). 6009:Mathematische Zeitschrift 5741:"GIMPS Milestones Report" 5579:edition: vol. 385, 58–61. 5114:superior highly composite 1618:centered nonagonal number 1491:{\displaystyle (2^{p}-1)} 1292:one-to-one correspondence 1013:and perfect numbers. For 9228:Euler's totient function 9012:Euler–Jacobi pseudoprime 8287:Other polynomial numbers 7827:Constrained divisor sums 7431:10.1515/crll.1941.183.98 7227:The Mathematical Gazette 5797:University of St Andrews 5431:{\displaystyle 2^{p}-1,} 5172:itself, come from Greek 4158:More generally, if all 2 3356:is not divisible by 105. 3330:harmonic divisor numbers 1235:proved that the formula 1087:are prime; for example, 341:, and the mathematician 231:{\displaystyle q(q+1)/2} 161:sum-of-divisors function 9042:Somer–Lucas pseudoprime 9032:Lucas–Carmichael number 8867:Lazy caterer's sequence 7639:"8128: Perfect Numbers" 7633:, math forum at Drexel. 7448:S.-B. Bayer. Akad. Wiss 7081:Colloquium Mathematicum 5348:{\displaystyle 2^{p}-1} 5304:Harmonic divisor number 5289:Multiply perfect number 4951:{\displaystyle 2^{n}+1} 3339:Any odd perfect number 1561:{\displaystyle 2^{p-1}} 1528:{\displaystyle 2^{p}-1} 1220:{\displaystyle 2^{n}-1} 1121:{\displaystyle 2^{p}-1} 1076:{\displaystyle 2^{p}-1} 1039:{\displaystyle 2^{p}-1} 994:{\displaystyle 2^{p}-1} 579:{\displaystyle 2^{p}-1} 430:{\displaystyle 2^{n}-1} 318:. Two millennia later, 287:{\displaystyle 2^{p}-1} 30:For the 2012 film, see 8917:Wedderburn–Etherington 8317:Lucky numbers of Euler 7031: 5438:which is the case for 5432: 5368:2 − 1 = 2047 = 23 × 89 5349: 5299:Unitary perfect number 5242: 5153: 5063:of numbers under 100: 5023: 4986: 4952: 4916: 4832: 4725: 4540: 4479: + 1 is 28 ( 4455: 4433: 4368: 4265: 4070: 3963: 3877: 3762: 3683: 3602: 3488: 3448: 3412: 3268: 2885: 2820: 2757: 2628: 2469: 1700: 1654: 1610: 1562: 1529: 1492: 1453: 1354: 1284: 1221: 1188: 1122: 1089:2 − 1 = 2047 = 23 × 89 1077: 1040: 995: 960: 647: 580: 547: 431: 398: 314:—what is now called a 308: 288: 252: 232: 153: 126: 42: 9205:Prime omega functions 9022:Frobenius pseudoprime 8812:Combinatorial numbers 8681:Centered dodecahedral 8474:Primary pseudoperfect 7708:Integer factorization 7371:Redmond, Don (1996). 7198:Yan, Song Y. (2012), 7103:10.4064/cm7339-3-2018 7032: 6794:Cohen, G. L. (1987). 6686:Archiv der Mathematik 6243:Iannucci, DE (2000). 6146:Iannucci, DE (1999). 5594:Commentary on Genesis 5433: 5350: 5248:-perfect numbers, or 5243: 5059: 5024: 4987: 4953: 4917: 4852:Ore's harmonic number 4833: 4726: 4541: 4434: 4369: 4266: 4071: 3964: 3878: 3763: 3684: 3603: 3489: 3449: 3413: 3269: 2886: 2833:Owing to their form, 2821: 2758: 2629: 2470: 1701: 1655: 1611: 1563: 1530: 1493: 1454: 1355: 1285: 1222: 1189: 1123: 1078: 1041: 996: 961: 648: 581: 548: 432: 399: 309: 294:for positive integer 289: 253: 233: 154: 127: 40: 32:Perfect Number (film) 9664:-composition related 9464:Arithmetic functions 9066:Arithmetic functions 9002:Elliptic pseudoprime 8686:Centered icosahedral 8666:Centered tetrahedral 7411:D.E. Joyce's website 7001: 6844:Kanold, Hans-Joachim 5783:Robertson, Edmund F. 5710:Peterson, I (2002). 5683:Pickover, C (2001). 5406: 5402:will be a factor of 5376:Sophie Germain prime 5326: 5294:Superperfect numbers 5228: 5047:perfect number is 6. 5000: 4969: 4929: 4871: 4738: 4557: 4505: 4378: 4327: 4210: 3975: 3889: 3773: 3701: 3655: 3523: 3461: 3424: 3385: 2908: 2902:zeros; for example: 2837: 2775: 2771:numbers of the form 2712: 2481: 1712: 1664: 1624: 1576: 1539: 1506: 1463: 1408: 1309: 1296:Euclid–Euler theorem 1239: 1198: 1143: 1099: 1054: 1017: 972: 665: 599: 557: 502: 475:Euclid–Euler theorem 469:Even perfect numbers 408: 353: 324:Euclid–Euler theorem 298: 265: 242: 199: 136: 91: 9590:Kaprekar's constant 9110:Colossally abundant 8997:Catalan pseudoprime 8897:Schröder–Hipparchus 8676:Centered octahedral 8552:Centered heptagonal 8542:Centered pentagonal 8532:Centered triangular 8132:and related numbers 7920:Colossally abundant 7751:Factorization forms 7517:, Birkhauser, 1985. 7045:Fibonacci Quarterly 6912:Fibonacci Quarterly 6648:Fibonacci Quarterly 6401:2007MaCom..76.2109N 6264:2000MaCom..69..867I 6167:1999MaCom..68.1749I 6089:2008MaCom..77.1859G 6042:Roberts, T (2008). 5781:O'Connor, John J.; 5577:Sources ChrĂ©tiennes 5274:Hyperperfect number 5110:Colossally abundant 4861:trapezoidal numbers 3640:≡ Î± ≡ 1 ( 3594: 3566: 3370:≡ 117 (mod 468) or 3295:Odd perfect numbers 2767:and, in fact, with 443:Philo of Alexandria 10008:Mathematics portal 9950:Aronson's sequence 9696:Smarandache–Wellin 9453:-dependent numbers 9160:Primitive abundant 9047:Strong pseudoprime 9037:Perrin pseudoprime 9017:Fermat pseudoprime 8957:Wolstenholme prime 8781:Squared triangular 8567:Centered decagonal 8562:Centered nonagonal 8557:Centered octagonal 8547:Centered hexagonal 7905:Primitive abundant 7893:With many divisors 7594:Weisstein, Eric W. 7470:Hagis, P. (1973). 7317:10.1007/BF01350108 7282:10.1007/BF01901120 7027: 6757:(279): 1753?1776. 6698:10.1007/BF01220877 6551:(289): 2435–2439. 6385:(260): 2109–2126. 6342:(295): 2549–2567. 6161:(228): 1749–1760. 6083:(263): 1859–1868. 6021:10.1007/BF02230691 5970:(279): 1869–1877. 5909:2006-12-29 at the 5832:Weisstein, Eric W. 5634:David Eugene Smith 5428: 5386:is also prime—and 5345: 5257:semiperfect number 5238: 5154: 5079:Primitive abundant 5019: 4982: 4948: 4912: 4865:triangular numbers 4828: 4721: 4536: 4429: 4364: 4261: 4066: 3959: 3873: 3758: 3679: 3598: 3570: 3542: 3484: 3444: 3408: 3326:heuristic argument 3264: 3262: 2881: 2816: 2753: 2698:8 + 1 + 2 + 8 = 19 2624: 2465: 2463: 1696: 1650: 1606: 1604: 1558: 1525: 1488: 1449: 1397:whether there are 1350: 1280: 1217: 1184: 1118: 1095:up to 68,874,199, 1073: 1036: 991: 956: 954: 643: 576: 543: 427: 394: 304: 284: 248: 228: 149: 122: 43: 10034:Integer sequences 10016: 10015: 9994: 9993: 9963: 9962: 9927: 9926: 9891: 9890: 9855: 9854: 9815: 9814: 9811: 9810: 9630: 9629: 9440: 9439: 9329: 9328: 9325: 9324: 9271:Aliquot sequences 9082:Divisor functions 9055: 9054: 9027:Lucas pseudoprime 9007:Euler pseudoprime 8992:Carmichael number 8970: 8969: 8925: 8924: 8802: 8801: 8798: 8797: 8794: 8793: 8755: 8754: 8643: 8642: 8600:Square triangular 8492: 8491: 8439: 8438: 8391: 8390: 8325: 8324: 8277: 8276: 8215: 8214: 8082: 8081: 5631:, Clm 14908. See 5564:triangular number 5533:"Perfect numbers" 5498:Caldwell, Chris, 5355:are congruent to 5250:Granville numbers 5031:little-o notation 5014: 4980: 4713: 4692: 4659: 4646: 4633: 4620: 4607: 4594: 4581: 4568: 4281:, ...,  4259: 4189:, ...,  4089:, ...,  4052: 4026: 4006: 3986: 3956: 3871: 3674: 3625:, ...,  3479: 3442: 3403: 3334:Descartes numbers 3278:pernicious number 2895:ones followed by 2570: 1687: 1647: 1603: 1500:triangular number 459:Ismail ibn FallĆ«s 451:Didymus the Blind 339:Greek mathematics 307:{\displaystyle p} 251:{\displaystyle q} 16:(Redirected from 10056: 10029:Divisor function 10006: 9969: 9938:Natural language 9933: 9897: 9865:Generated via a 9861: 9821: 9726:Digit-reassembly 9691:Self-descriptive 9495: 9460: 9446: 9397:Lucas–Carmichael 9387:Harmonic divisor 9335: 9261:Sparsely totient 9236:Highly cototient 9145:Multiply perfect 9135:Highly composite 9078: 9061: 8976: 8931: 8912:Telephone number 8808: 8766: 8747:Square pyramidal 8729:Stella octangula 8654: 8520: 8511: 8503:Figurate numbers 8498: 8445: 8397: 8331: 8283: 8221: 8125: 8109: 8102: 8095: 8086: 8059:Harmonic divisor 7945:Aliquot sequence 7925:Highly composite 7849:Multiply perfect 7745: 7723:Divisor function 7689: 7682: 7675: 7666: 7661: 7659: 7658: 7649:. Archived from 7612: 7607: 7606: 7597:"Perfect Number" 7577: 7564:"Perfect number" 7552: 7528: 7503: 7493: 7484:(124): 951–953. 7455: 7442: 7390: 7388: 7368: 7362: 7361: 7348: 7342: 7335: 7329: 7328: 7300: 7294: 7293: 7265: 7259: 7258: 7222: 7216: 7214: 7195: 7189: 7187: 7185: 7161: 7155: 7154: 7142: 7136: 7129: 7123: 7122: 7096: 7076: 7070: 7069: 7041: 7036: 7034: 7033: 7028: 7026: 7025: 7013: 7012: 6992: 6986: 6985: 6967: 6943: 6937: 6936: 6908: 6899: 6890: 6889: 6840: 6834: 6833: 6815: 6791: 6785: 6784: 6766: 6746: 6737: 6726: 6725: 6681: 6675: 6674: 6662: 6656: 6655: 6643: 6637: 6636: 6634: 6632: 6612: 6606: 6605: 6603: 6601: 6596: 6578: 6569: 6563: 6562: 6560: 6534: 6528: 6527: 6525: 6523: 6503: 6497: 6496: 6494: 6470: 6464: 6463: 6461: 6459: 6446: 6437: 6428: 6427: 6425: 6423: 6394: 6376: 6367: 6361: 6360: 6358: 6356: 6351: 6333: 6324: 6318: 6317: 6315: 6313: 6300: 6291: 6285: 6284: 6282: 6280: 6275: 6258:(230): 867–879. 6249: 6240: 6234: 6232: 6214: 6205:(6): 1183–1189. 6194: 6188: 6187: 6185: 6183: 6178: 6152: 6143: 6137: 6136: 6127:(6): 1537–1540. 6116: 6110: 6109: 6107: 6105: 6100: 6074: 6065: 6059: 6058: 6048: 6039: 6033: 6032: 6004: 5998: 5997: 5979: 5959: 5950: 5939: 5938: 5936: 5934: 5919: 5913: 5900: 5894: 5893: 5891: 5889: 5880: 5872: 5866: 5865: 5852: 5846: 5845: 5844: 5835:"Perfect Number" 5827: 5821: 5820: 5818: 5817: 5806: 5800: 5799: 5778: 5772: 5771: 5765: 5757: 5755: 5753: 5737: 5728: 5727: 5707: 5701: 5700: 5680: 5674: 5673: 5660: 5654: 5653: 5626: 5620: 5613: 5607: 5606: 5600: 5586: 5580: 5573: 5567: 5554: 5548: 5547: 5545: 5543: 5529: 5523: 5522: 5509: 5503: 5496: 5490: 5489: 5487: 5486: 5476:"A000396 - OEIS" 5472: 5455: 5453: 5444: 5442: 5437: 5435: 5434: 5429: 5418: 5417: 5401: 5393: 5385: 5373: 5369: 5365: 5354: 5352: 5351: 5346: 5338: 5337: 5320: 5247: 5245: 5244: 5239: 5237: 5236: 5222:aliquot sequence 5219: 5186:practical number 5147: 5138: 5129: 5120: 5107: 5101:highly composite 5094: 5085: 5076: 5067: 5052:Related concepts 5028: 5026: 5025: 5020: 5015: 5010: 4991: 4989: 4988: 4983: 4981: 4976: 4957: 4955: 4954: 4949: 4941: 4940: 4921: 4919: 4918: 4913: 4902: 4901: 4889: 4888: 4837: 4835: 4834: 4829: 4818: 4804: 4790: 4776: 4762: 4748: 4734:For 28, we have 4730: 4728: 4727: 4722: 4714: 4709: 4698: 4693: 4688: 4665: 4660: 4652: 4647: 4639: 4634: 4626: 4621: 4613: 4608: 4600: 4595: 4587: 4582: 4574: 4569: 4561: 4545: 4543: 4542: 4537: 4517: 4516: 4438: 4436: 4435: 4430: 4428: 4427: 4426: 4425: 4409: 4408: 4373: 4371: 4370: 4365: 4348: 4347: 4314: 4270: 4268: 4267: 4262: 4260: 4255: 4232: 4143: â‰Ą 1 ( 4127: â‰Ą 2 ( 4111: â‰Ą 1 ( 4075: 4073: 4072: 4067: 4053: 4051: 4050: 4038: 4027: 4025: 4024: 4012: 4007: 4005: 4004: 3992: 3987: 3979: 3968: 3966: 3965: 3960: 3958: 3957: 3949: 3937: 3936: 3924: 3923: 3914: 3913: 3904: 3903: 3882: 3880: 3879: 3874: 3872: 3867: 3853: 3848: 3847: 3826: 3825: 3810: 3809: 3794: 3793: 3767: 3765: 3764: 3759: 3757: 3756: 3752: 3751: 3733: 3732: 3688: 3686: 3685: 3680: 3675: 3670: 3659: 3607: 3605: 3604: 3599: 3593: 3592: 3591: 3578: 3565: 3564: 3563: 3550: 3541: 3540: 3493: 3491: 3490: 3485: 3480: 3478: 3473: 3465: 3453: 3451: 3450: 3445: 3443: 3441: 3436: 3428: 3417: 3415: 3414: 3409: 3404: 3402: 3397: 3389: 3366:≡ 1 (mod 12) or 3324:has presented a 3302: 3289:Related concepts 3285:practical number 3273: 3271: 3270: 3265: 3263: 3259: 3258: 3242: 3241: 3229: 3228: 3216: 3215: 3203: 3202: 3190: 3189: 3177: 3176: 3164: 3163: 3147: 3146: 3133: 3132: 3118: 3117: 3105: 3104: 3092: 3091: 3079: 3078: 3066: 3065: 3051: 3050: 3037: 3036: 3022: 3021: 3009: 3008: 2996: 2995: 2981: 2980: 2967: 2966: 2952: 2951: 2939: 2938: 2924: 2923: 2901: 2894: 2890: 2888: 2887: 2882: 2868: 2867: 2855: 2854: 2829: 2825: 2823: 2822: 2817: 2806: 2805: 2793: 2792: 2766: 2762: 2760: 2759: 2754: 2743: 2742: 2730: 2729: 2707: 2703: 2699: 2691: 2683: 2675: 2667: 2659: 2651: 2643: 2633: 2631: 2630: 2625: 2623: 2622: 2618: 2604: 2603: 2571: 2566: 2556: 2555: 2531: 2530: 2517: 2506: 2505: 2498: 2497: 2474: 2472: 2471: 2466: 2464: 2460: 2459: 2447: 2446: 2434: 2433: 2415: 2414: 2402: 2401: 2389: 2388: 2373: 2372: 2371: 2322: 2311: 2310: 2298: 2297: 2274: 2273: 2261: 2260: 2248: 2247: 2235: 2234: 2222: 2221: 2209: 2208: 2196: 2195: 2183: 2182: 2167: 2166: 2165: 2116: 2105: 2104: 2092: 2091: 2068: 2067: 2055: 2054: 2042: 2041: 2029: 2028: 2013: 2012: 2011: 1962: 1951: 1950: 1938: 1937: 1914: 1913: 1901: 1900: 1885: 1884: 1883: 1834: 1823: 1822: 1810: 1809: 1762: 1751: 1750: 1738: 1737: 1705: 1703: 1702: 1697: 1689: 1688: 1683: 1672: 1659: 1657: 1656: 1651: 1649: 1648: 1643: 1632: 1615: 1613: 1612: 1607: 1605: 1599: 1592: 1591: 1581: 1570:hexagonal number 1567: 1565: 1564: 1559: 1557: 1556: 1534: 1532: 1531: 1526: 1518: 1517: 1497: 1495: 1494: 1489: 1478: 1477: 1458: 1456: 1455: 1450: 1439: 1438: 1426: 1425: 1392: 1388: 1384: 1372: 1366: 1359: 1357: 1356: 1351: 1340: 1339: 1327: 1326: 1289: 1287: 1286: 1281: 1270: 1269: 1257: 1256: 1226: 1224: 1223: 1218: 1210: 1209: 1193: 1191: 1190: 1185: 1174: 1173: 1161: 1160: 1127: 1125: 1124: 1119: 1111: 1110: 1094: 1090: 1086: 1082: 1080: 1079: 1074: 1066: 1065: 1049: 1045: 1043: 1042: 1037: 1029: 1028: 1000: 998: 997: 992: 984: 983: 965: 963: 962: 957: 955: 924: 923: 911: 910: 853: 852: 840: 839: 782: 781: 769: 768: 711: 710: 698: 697: 656: 652: 650: 649: 644: 630: 629: 617: 616: 592:, Prop. IX.36). 585: 583: 582: 577: 569: 568: 552: 550: 549: 544: 533: 532: 520: 519: 482: 440: 436: 434: 433: 428: 420: 419: 403: 401: 400: 395: 384: 383: 371: 370: 313: 311: 310: 305: 293: 291: 290: 285: 277: 276: 257: 255: 254: 249: 237: 235: 234: 229: 224: 178: 177: 158: 156: 155: 150: 148: 147: 131: 129: 128: 123: 103: 102: 55:positive integer 21: 10064: 10063: 10059: 10058: 10057: 10055: 10054: 10053: 10049:Perfect numbers 10044:Mersenne primes 10019: 10018: 10017: 10012: 9990: 9986:Strobogrammatic 9977: 9959: 9941: 9923: 9905: 9887: 9869: 9851: 9828: 9807: 9791: 9750:Divisor-related 9745: 9705: 9656: 9626: 9563: 9547: 9526: 9493: 9466: 9454: 9436: 9348: 9347:related numbers 9321: 9298: 9265: 9256:Perfect totient 9222: 9199: 9130:Highly abundant 9072: 9051: 8983: 8966: 8938: 8921: 8907:Stirling second 8813: 8790: 8751: 8733: 8690: 8639: 8576: 8537:Centered square 8505: 8488: 8450: 8435: 8402: 8387: 8339: 8338:defined numbers 8321: 8288: 8273: 8244:Double Mersenne 8230: 8211: 8133: 8119: 8117:natural numbers 8113: 8083: 8078: 8022: 7978: 7939: 7910:Highly abundant 7888: 7869:Unitary perfect 7822: 7746: 7737: 7718:Unitary divisor 7696: 7693: 7656: 7654: 7637:Grimes, James. 7636: 7631:Perfect Numbers 7592: 7591: 7562: 7559: 7541: 7520: 7491:10.2307/2005530 7469: 7463: 7461:Further reading 7458: 7445: 7425:(183): 98–109. 7416: 7399: 7394: 7393: 7385: 7370: 7369: 7365: 7350: 7349: 7345: 7336: 7332: 7302: 7301: 7297: 7267: 7266: 7262: 7239:10.2307/3619053 7224: 7223: 7219: 7212: 7197: 7196: 7192: 7163: 7162: 7158: 7144: 7143: 7139: 7130: 7126: 7078: 7077: 7073: 7039: 7014: 7004: 6999: 6998: 6994: 6993: 6989: 6945: 6944: 6940: 6906: 6901: 6900: 6893: 6842: 6841: 6837: 6793: 6792: 6788: 6744: 6739: 6738: 6729: 6683: 6682: 6678: 6664: 6663: 6659: 6645: 6644: 6640: 6630: 6628: 6614: 6613: 6609: 6599: 6597: 6576: 6571: 6570: 6566: 6536: 6535: 6531: 6521: 6519: 6505: 6504: 6500: 6472: 6471: 6467: 6457: 6455: 6444: 6439: 6438: 6431: 6421: 6419: 6374: 6369: 6368: 6364: 6354: 6352: 6331: 6326: 6325: 6321: 6311: 6309: 6298: 6293: 6292: 6288: 6278: 6276: 6247: 6242: 6241: 6237: 6196: 6195: 6191: 6181: 6179: 6150: 6145: 6144: 6140: 6118: 6117: 6113: 6103: 6101: 6072: 6067: 6066: 6062: 6046: 6041: 6040: 6036: 6006: 6005: 6001: 5957: 5952: 5951: 5942: 5932: 5930: 5928:Quanta Magazine 5921: 5920: 5916: 5911:Wayback Machine 5901: 5897: 5887: 5885: 5878: 5874: 5873: 5869: 5854: 5853: 5849: 5830: 5829: 5828: 5824: 5815: 5813: 5808: 5807: 5803: 5780: 5779: 5775: 5758: 5751: 5749: 5739: 5738: 5731: 5724: 5709: 5708: 5704: 5697: 5682: 5681: 5677: 5662: 5661: 5657: 5650: 5632: 5627: 5623: 5615:Roshdi Rashed, 5614: 5610: 5598: 5588: 5587: 5583: 5574: 5570: 5555: 5551: 5541: 5539: 5531: 5530: 5526: 5511: 5510: 5506: 5497: 5493: 5484: 5482: 5474: 5473: 5469: 5464: 5459: 5458: 5445: 5440: 5439: 5409: 5404: 5403: 5395: 5387: 5379: 5371: 5367: 5366:. For example, 5356: 5329: 5324: 5323: 5322:All factors of 5321: 5317: 5312: 5270: 5226: 5225: 5199: 5158:proper divisors 5152: 5145: 5143: 5136: 5134: 5127: 5125: 5118: 5116: 5105: 5103: 5092: 5090: 5088:Highly abundant 5083: 5081: 5074: 5072: 5065: 5054: 4998: 4997: 4967: 4966: 4932: 4927: 4926: 4893: 4874: 4869: 4868: 4736: 4735: 4699: 4666: 4555: 4554: 4553:For 6, we have 4508: 4503: 4502: 4460: 4400: 4392: 4387: 4376: 4375: 4339: 4325: 4324: 4309: 4300: 4294: 4289: 4280: 4208: 4207: 4197: 4188: 4166: 4142: 4126: 4110: 4097: 4088: 4042: 4016: 3996: 3973: 3972: 3944: 3928: 3915: 3905: 3895: 3887: 3886: 3854: 3839: 3817: 3801: 3785: 3771: 3770: 3737: 3718: 3710: 3699: 3698: 3660: 3653: 3652: 3633: 3624: 3583: 3555: 3532: 3521: 3520: 3466: 3459: 3458: 3429: 3422: 3421: 3390: 3383: 3382: 3374:≡ 81 (mod 324). 3362:is of the form 3317:Jacques LefĂšvre 3313: 3312: 3307: 3304: 3300: 3297: 3261: 3260: 3250: 3245: 3233: 3220: 3207: 3194: 3181: 3168: 3155: 3151: 3138: 3135: 3134: 3124: 3119: 3109: 3096: 3083: 3070: 3057: 3055: 3042: 3039: 3038: 3028: 3023: 3013: 3000: 2987: 2985: 2972: 2969: 2968: 2958: 2953: 2943: 2930: 2928: 2915: 2906: 2905: 2896: 2892: 2859: 2840: 2835: 2834: 2827: 2797: 2778: 2773: 2772: 2764: 2763:with odd prime 2734: 2715: 2710: 2709: 2705: 2701: 2697: 2689: 2685: 2681: 2677: 2673: 2669: 2665: 2661: 2657: 2653: 2649: 2645: 2641: 2637: 2595: 2587: 2547: 2522: 2518: 2489: 2484: 2479: 2478: 2462: 2461: 2451: 2438: 2425: 2406: 2393: 2380: 2369: 2368: 2321: 2302: 2289: 2282: 2276: 2275: 2265: 2252: 2239: 2226: 2213: 2200: 2187: 2174: 2163: 2162: 2115: 2096: 2083: 2076: 2070: 2069: 2059: 2046: 2033: 2020: 2009: 2008: 1961: 1942: 1929: 1922: 1916: 1915: 1905: 1892: 1881: 1880: 1833: 1814: 1801: 1794: 1788: 1787: 1761: 1742: 1729: 1722: 1710: 1709: 1673: 1667: 1662: 1661: 1633: 1627: 1622: 1621: 1583: 1582: 1574: 1573: 1542: 1537: 1536: 1509: 1504: 1503: 1469: 1461: 1460: 1430: 1411: 1406: 1405: 1399:infinitely many 1390: 1386: 1382: 1368: 1364: 1331: 1312: 1307: 1306: 1261: 1242: 1237: 1236: 1201: 1196: 1195: 1165: 1146: 1141: 1140: 1102: 1097: 1096: 1092: 1088: 1084: 1057: 1052: 1051: 1047: 1020: 1015: 1014: 1003:Mersenne primes 975: 970: 969: 953: 952: 915: 902: 894: 882: 881: 844: 831: 823: 811: 810: 773: 760: 752: 740: 739: 702: 689: 681: 663: 662: 654: 621: 602: 597: 596: 560: 555: 554: 524: 505: 500: 499: 493: 492: 487: 484: 480: 477: 471: 438: 411: 406: 405: 375: 356: 351: 350: 335: 296: 295: 268: 263: 262: 240: 239: 197: 196: 189:complete number 176:τέλΔÎčÎżÏ‚ ጀρÎčΞΌός 139: 134: 133: 94: 89: 88: 35: 28: 23: 22: 18:Perfect numbers 15: 12: 11: 5: 10062: 10060: 10052: 10051: 10046: 10041: 10036: 10031: 10021: 10020: 10014: 10013: 10011: 10010: 9999: 9996: 9995: 9992: 9991: 9989: 9988: 9982: 9979: 9978: 9972: 9965: 9964: 9961: 9960: 9958: 9957: 9952: 9946: 9943: 9942: 9936: 9929: 9928: 9925: 9924: 9922: 9921: 9919:Sorting number 9916: 9914:Pancake number 9910: 9907: 9906: 9900: 9893: 9892: 9889: 9888: 9886: 9885: 9880: 9874: 9871: 9870: 9864: 9857: 9856: 9853: 9852: 9850: 9849: 9844: 9839: 9833: 9830: 9829: 9826:Binary numbers 9824: 9817: 9816: 9813: 9812: 9809: 9808: 9806: 9805: 9799: 9797: 9793: 9792: 9790: 9789: 9784: 9779: 9774: 9769: 9764: 9759: 9753: 9751: 9747: 9746: 9744: 9743: 9738: 9733: 9728: 9723: 9717: 9715: 9707: 9706: 9704: 9703: 9698: 9693: 9688: 9683: 9678: 9673: 9667: 9665: 9658: 9657: 9655: 9654: 9653: 9652: 9641: 9639: 9636:P-adic numbers 9632: 9631: 9628: 9627: 9625: 9624: 9623: 9622: 9612: 9607: 9602: 9597: 9592: 9587: 9582: 9577: 9571: 9569: 9565: 9564: 9562: 9561: 9555: 9553: 9552:Coding-related 9549: 9548: 9546: 9545: 9540: 9534: 9532: 9528: 9527: 9525: 9524: 9519: 9514: 9509: 9503: 9501: 9492: 9491: 9490: 9489: 9487:Multiplicative 9484: 9473: 9471: 9456: 9455: 9451:Numeral system 9449: 9442: 9441: 9438: 9437: 9435: 9434: 9429: 9424: 9419: 9414: 9409: 9404: 9399: 9394: 9389: 9384: 9379: 9374: 9369: 9364: 9359: 9353: 9350: 9349: 9338: 9331: 9330: 9327: 9326: 9323: 9322: 9320: 9319: 9314: 9308: 9306: 9300: 9299: 9297: 9296: 9291: 9286: 9281: 9275: 9273: 9267: 9266: 9264: 9263: 9258: 9253: 9248: 9243: 9241:Highly totient 9238: 9232: 9230: 9224: 9223: 9221: 9220: 9215: 9209: 9207: 9201: 9200: 9198: 9197: 9192: 9187: 9182: 9177: 9172: 9167: 9162: 9157: 9152: 9147: 9142: 9137: 9132: 9127: 9122: 9117: 9112: 9107: 9102: 9097: 9095:Almost perfect 9092: 9086: 9084: 9074: 9073: 9064: 9057: 9056: 9053: 9052: 9050: 9049: 9044: 9039: 9034: 9029: 9024: 9019: 9014: 9009: 9004: 8999: 8994: 8988: 8985: 8984: 8979: 8972: 8971: 8968: 8967: 8965: 8964: 8959: 8954: 8949: 8943: 8940: 8939: 8934: 8927: 8926: 8923: 8922: 8920: 8919: 8914: 8909: 8904: 8902:Stirling first 8899: 8894: 8889: 8884: 8879: 8874: 8869: 8864: 8859: 8854: 8849: 8844: 8839: 8834: 8829: 8824: 8818: 8815: 8814: 8811: 8804: 8803: 8800: 8799: 8796: 8795: 8792: 8791: 8789: 8788: 8783: 8778: 8772: 8770: 8763: 8757: 8756: 8753: 8752: 8750: 8749: 8743: 8741: 8735: 8734: 8732: 8731: 8726: 8721: 8716: 8711: 8706: 8700: 8698: 8692: 8691: 8689: 8688: 8683: 8678: 8673: 8668: 8662: 8660: 8651: 8645: 8644: 8641: 8640: 8638: 8637: 8632: 8627: 8622: 8617: 8612: 8607: 8602: 8597: 8592: 8586: 8584: 8578: 8577: 8575: 8574: 8569: 8564: 8559: 8554: 8549: 8544: 8539: 8534: 8528: 8526: 8517: 8507: 8506: 8501: 8494: 8493: 8490: 8489: 8487: 8486: 8481: 8476: 8471: 8466: 8461: 8455: 8452: 8451: 8448: 8441: 8440: 8437: 8436: 8434: 8433: 8428: 8423: 8418: 8413: 8407: 8404: 8403: 8400: 8393: 8392: 8389: 8388: 8386: 8385: 8380: 8375: 8370: 8365: 8360: 8355: 8350: 8344: 8341: 8340: 8334: 8327: 8326: 8323: 8322: 8320: 8319: 8314: 8309: 8304: 8299: 8293: 8290: 8289: 8286: 8279: 8278: 8275: 8274: 8272: 8271: 8266: 8261: 8256: 8251: 8246: 8241: 8235: 8232: 8231: 8224: 8217: 8216: 8213: 8212: 8210: 8209: 8204: 8199: 8194: 8189: 8184: 8179: 8174: 8169: 8164: 8159: 8154: 8149: 8144: 8138: 8135: 8134: 8128: 8121: 8120: 8114: 8112: 8111: 8104: 8097: 8089: 8080: 8079: 8077: 8076: 8071: 8066: 8061: 8056: 8051: 8046: 8041: 8036: 8030: 8028: 8024: 8023: 8021: 8020: 8015: 8010: 8005: 8000: 7995: 7989: 7987: 7980: 7979: 7977: 7976: 7971: 7966: 7956: 7950: 7948: 7941: 7940: 7938: 7937: 7932: 7927: 7922: 7917: 7912: 7907: 7902: 7896: 7894: 7890: 7889: 7887: 7886: 7881: 7876: 7871: 7866: 7861: 7856: 7851: 7846: 7841: 7839:Almost perfect 7836: 7830: 7828: 7824: 7823: 7821: 7820: 7815: 7810: 7805: 7800: 7795: 7790: 7785: 7780: 7775: 7770: 7765: 7760: 7754: 7752: 7748: 7747: 7740: 7738: 7736: 7735: 7730: 7725: 7720: 7715: 7710: 7704: 7702: 7698: 7697: 7694: 7692: 7691: 7684: 7677: 7669: 7663: 7662: 7634: 7628: 7622: 7619:OddPerfect.org 7616: 7608: 7589: 7584: 7578: 7558: 7557:External links 7555: 7554: 7553: 7539: 7518: 7511: 7504: 7467: 7462: 7459: 7457: 7456: 7443: 7414: 7400: 7398: 7395: 7392: 7391: 7383: 7363: 7352:Dickson, L. E. 7343: 7330: 7311:(4): 390–392. 7295: 7276:(6): 442–443. 7260: 7217: 7210: 7190: 7183:10.4171/EM/149 7176:(3): 121–126. 7156: 7137: 7124: 7071: 7024: 7021: 7017: 7011: 7007: 6987: 6938: 6891: 6856:(1): 129–146. 6835: 6806:(2): 280–286. 6786: 6727: 6676: 6657: 6638: 6607: 6564: 6529: 6498: 6485:(3): 353–359. 6465: 6429: 6362: 6319: 6286: 6235: 6189: 6138: 6111: 6060: 6034: 5999: 5940: 5914: 5903:Oddperfect.org 5895: 5867: 5856:Dickson, L. E. 5847: 5822: 5812:. Mersenne.org 5801: 5773: 5729: 5722: 5702: 5695: 5675: 5664:Dickson, L. E. 5655: 5648: 5621: 5608: 5581: 5568: 5549: 5524: 5513:Dickson, L. E. 5504: 5491: 5466: 5465: 5463: 5460: 5457: 5456: 5427: 5424: 5421: 5416: 5412: 5344: 5341: 5336: 5332: 5314: 5313: 5311: 5308: 5307: 5306: 5301: 5296: 5291: 5286: 5281: 5279:Leinster group 5276: 5269: 5266: 5235: 5144: 5135: 5126: 5117: 5104: 5091: 5082: 5073: 5064: 5053: 5050: 5049: 5048: 5041: 5034: 5018: 5013: 5008: 5005: 4979: 4974: 4959: 4947: 4944: 4939: 4935: 4911: 4908: 4905: 4900: 4896: 4892: 4887: 4884: 4881: 4877: 4857: 4856: 4855: 4841: 4840: 4839: 4827: 4824: 4821: 4817: 4813: 4810: 4807: 4803: 4799: 4796: 4793: 4789: 4785: 4782: 4779: 4775: 4771: 4768: 4765: 4761: 4757: 4754: 4751: 4747: 4743: 4732: 4720: 4717: 4712: 4708: 4705: 4702: 4696: 4691: 4687: 4684: 4681: 4678: 4675: 4672: 4669: 4663: 4658: 4655: 4650: 4645: 4642: 4637: 4632: 4629: 4624: 4619: 4616: 4611: 4606: 4603: 4598: 4593: 4590: 4585: 4580: 4577: 4572: 4567: 4564: 4535: 4532: 4529: 4526: 4523: 4520: 4515: 4511: 4491: 4484: 4459: 4456: 4443: 4442: 4441: 4440: 4424: 4421: 4418: 4415: 4412: 4407: 4403: 4399: 4395: 4390: 4386: 4383: 4363: 4360: 4357: 4354: 4351: 4346: 4342: 4338: 4335: 4332: 4322: 4305: 4298: 4291: 4285: 4278: 4272: 4258: 4253: 4250: 4247: 4244: 4241: 4238: 4235: 4231: 4227: 4224: 4221: 4218: 4215: 4193: 4186: 4180: 4162: 4156: 4138: 4132: 4122: 4116: 4106: 4093: 4086: 4080: 4079: 4078: 4077: 4065: 4062: 4059: 4056: 4049: 4045: 4041: 4036: 4033: 4030: 4023: 4019: 4015: 4010: 4003: 3999: 3995: 3990: 3985: 3982: 3970: 3955: 3952: 3947: 3943: 3940: 3935: 3931: 3927: 3922: 3918: 3912: 3908: 3902: 3898: 3894: 3884: 3870: 3866: 3863: 3860: 3857: 3851: 3846: 3842: 3838: 3835: 3832: 3829: 3824: 3820: 3816: 3813: 3808: 3804: 3800: 3797: 3792: 3788: 3784: 3781: 3778: 3768: 3755: 3750: 3747: 3744: 3740: 3736: 3731: 3728: 3725: 3721: 3717: 3713: 3709: 3706: 3696: 3689: 3678: 3673: 3669: 3666: 3663: 3645: 3635: 3629: 3622: 3610: 3609: 3608: 3597: 3590: 3586: 3582: 3577: 3573: 3569: 3562: 3558: 3554: 3549: 3545: 3539: 3535: 3531: 3528: 3515: 3514: 3513:is of the form 3508: 3494: 3483: 3477: 3472: 3469: 3455: 3440: 3435: 3432: 3418: 3407: 3401: 3396: 3393: 3375: 3357: 3351: 3322:Carl Pomerance 3308: 3305: 3299: 3296: 3293: 3257: 3253: 3249: 3246: 3240: 3236: 3232: 3227: 3223: 3219: 3214: 3210: 3206: 3201: 3197: 3193: 3188: 3184: 3180: 3175: 3171: 3167: 3162: 3158: 3152: 3150: 3145: 3141: 3137: 3136: 3131: 3127: 3123: 3120: 3116: 3112: 3108: 3103: 3099: 3095: 3090: 3086: 3082: 3077: 3073: 3069: 3064: 3060: 3056: 3054: 3049: 3045: 3041: 3040: 3035: 3031: 3027: 3024: 3020: 3016: 3012: 3007: 3003: 2999: 2994: 2990: 2986: 2984: 2979: 2975: 2971: 2970: 2965: 2961: 2957: 2954: 2950: 2946: 2942: 2937: 2933: 2929: 2927: 2922: 2918: 2914: 2913: 2880: 2877: 2874: 2871: 2866: 2862: 2858: 2853: 2850: 2847: 2843: 2815: 2812: 2809: 2804: 2800: 2796: 2791: 2788: 2785: 2781: 2770: 2752: 2749: 2746: 2741: 2737: 2733: 2728: 2725: 2722: 2718: 2690:= 3727815, ... 2687: 2679: 2671: 2663: 2655: 2647: 2639: 2621: 2617: 2613: 2610: 2607: 2602: 2598: 2594: 2590: 2586: 2583: 2580: 2577: 2574: 2569: 2565: 2562: 2559: 2554: 2550: 2546: 2543: 2540: 2537: 2534: 2529: 2525: 2521: 2515: 2512: 2509: 2504: 2501: 2496: 2492: 2487: 2458: 2454: 2450: 2445: 2441: 2437: 2432: 2428: 2424: 2421: 2418: 2413: 2409: 2405: 2400: 2396: 2392: 2387: 2383: 2379: 2376: 2374: 2370: 2367: 2364: 2361: 2358: 2355: 2352: 2349: 2346: 2343: 2340: 2337: 2334: 2331: 2328: 2325: 2323: 2320: 2317: 2314: 2309: 2305: 2301: 2296: 2292: 2288: 2285: 2283: 2281: 2278: 2277: 2272: 2268: 2264: 2259: 2255: 2251: 2246: 2242: 2238: 2233: 2229: 2225: 2220: 2216: 2212: 2207: 2203: 2199: 2194: 2190: 2186: 2181: 2177: 2173: 2170: 2168: 2164: 2161: 2158: 2155: 2152: 2149: 2146: 2143: 2140: 2137: 2134: 2131: 2128: 2125: 2122: 2119: 2117: 2114: 2111: 2108: 2103: 2099: 2095: 2090: 2086: 2082: 2079: 2077: 2075: 2072: 2071: 2066: 2062: 2058: 2053: 2049: 2045: 2040: 2036: 2032: 2027: 2023: 2019: 2016: 2014: 2010: 2007: 2004: 2001: 1998: 1995: 1992: 1989: 1986: 1983: 1980: 1977: 1974: 1971: 1968: 1965: 1963: 1960: 1957: 1954: 1949: 1945: 1941: 1936: 1932: 1928: 1925: 1923: 1921: 1918: 1917: 1912: 1908: 1904: 1899: 1895: 1891: 1888: 1886: 1882: 1879: 1876: 1873: 1870: 1867: 1864: 1861: 1858: 1855: 1852: 1849: 1846: 1843: 1840: 1837: 1835: 1832: 1829: 1826: 1821: 1817: 1813: 1808: 1804: 1800: 1797: 1795: 1793: 1790: 1789: 1786: 1783: 1780: 1777: 1774: 1771: 1768: 1765: 1763: 1760: 1757: 1754: 1749: 1745: 1741: 1736: 1732: 1728: 1725: 1723: 1721: 1718: 1717: 1695: 1692: 1686: 1682: 1679: 1676: 1670: 1646: 1642: 1639: 1636: 1630: 1602: 1598: 1595: 1590: 1586: 1555: 1552: 1549: 1545: 1524: 1521: 1516: 1512: 1487: 1484: 1481: 1476: 1472: 1468: 1448: 1445: 1442: 1437: 1433: 1429: 1424: 1421: 1418: 1414: 1379: 1378: 1349: 1346: 1343: 1338: 1334: 1330: 1325: 1322: 1319: 1315: 1279: 1276: 1273: 1268: 1264: 1260: 1255: 1252: 1249: 1245: 1233:Leonhard Euler 1229:Ibn al-Haytham 1216: 1213: 1208: 1204: 1183: 1180: 1177: 1172: 1168: 1164: 1159: 1156: 1153: 1149: 1138: 1117: 1114: 1109: 1105: 1072: 1069: 1064: 1060: 1035: 1032: 1027: 1023: 1009:, who studied 1007:Marin Mersenne 990: 987: 982: 978: 951: 948: 945: 942: 939: 936: 933: 930: 927: 922: 918: 914: 909: 905: 900: 897: 895: 893: 890: 887: 884: 883: 880: 877: 874: 871: 868: 865: 862: 859: 856: 851: 847: 843: 838: 834: 829: 826: 824: 822: 819: 816: 813: 812: 809: 806: 803: 800: 797: 794: 791: 788: 785: 780: 776: 772: 767: 763: 758: 755: 753: 751: 748: 745: 742: 741: 738: 735: 732: 729: 726: 723: 720: 717: 714: 709: 705: 701: 696: 692: 687: 684: 682: 680: 677: 674: 671: 670: 661:, as follows: 642: 639: 636: 633: 628: 624: 620: 615: 612: 609: 605: 575: 572: 567: 563: 542: 539: 536: 531: 527: 523: 518: 515: 512: 508: 488: 485: 479: 470: 467: 463:Pietro Cataldi 426: 423: 418: 414: 393: 390: 387: 382: 378: 374: 369: 366: 363: 359: 348: 334: 331: 320:Leonhard Euler 316:Mersenne prime 303: 283: 280: 275: 271: 247: 227: 223: 219: 216: 213: 210: 207: 204: 146: 142: 121: 118: 115: 112: 109: 106: 101: 97: 51:perfect number 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 10061: 10050: 10047: 10045: 10042: 10040: 10037: 10035: 10032: 10030: 10027: 10026: 10024: 10009: 10005: 10001: 10000: 9997: 9987: 9984: 9983: 9980: 9975: 9970: 9966: 9956: 9953: 9951: 9948: 9947: 9944: 9939: 9934: 9930: 9920: 9917: 9915: 9912: 9911: 9908: 9903: 9898: 9894: 9884: 9881: 9879: 9876: 9875: 9872: 9868: 9862: 9858: 9848: 9845: 9843: 9840: 9838: 9835: 9834: 9831: 9827: 9822: 9818: 9804: 9801: 9800: 9798: 9794: 9788: 9785: 9783: 9780: 9778: 9777:Polydivisible 9775: 9773: 9770: 9768: 9765: 9763: 9760: 9758: 9755: 9754: 9752: 9748: 9742: 9739: 9737: 9734: 9732: 9729: 9727: 9724: 9722: 9719: 9718: 9716: 9713: 9708: 9702: 9699: 9697: 9694: 9692: 9689: 9687: 9684: 9682: 9679: 9677: 9674: 9672: 9669: 9668: 9666: 9663: 9659: 9651: 9648: 9647: 9646: 9643: 9642: 9640: 9637: 9633: 9621: 9618: 9617: 9616: 9613: 9611: 9608: 9606: 9603: 9601: 9598: 9596: 9593: 9591: 9588: 9586: 9583: 9581: 9578: 9576: 9573: 9572: 9570: 9566: 9560: 9557: 9556: 9554: 9550: 9544: 9541: 9539: 9536: 9535: 9533: 9531:Digit product 9529: 9523: 9520: 9518: 9515: 9513: 9510: 9508: 9505: 9504: 9502: 9500: 9496: 9488: 9485: 9483: 9480: 9479: 9478: 9475: 9474: 9472: 9470: 9465: 9461: 9457: 9452: 9447: 9443: 9433: 9430: 9428: 9425: 9423: 9420: 9418: 9415: 9413: 9410: 9408: 9405: 9403: 9400: 9398: 9395: 9393: 9390: 9388: 9385: 9383: 9380: 9378: 9375: 9373: 9370: 9368: 9367:ErdƑs–Nicolas 9365: 9363: 9360: 9358: 9355: 9354: 9351: 9346: 9342: 9336: 9332: 9318: 9315: 9313: 9310: 9309: 9307: 9305: 9301: 9295: 9292: 9290: 9287: 9285: 9282: 9280: 9277: 9276: 9274: 9272: 9268: 9262: 9259: 9257: 9254: 9252: 9249: 9247: 9244: 9242: 9239: 9237: 9234: 9233: 9231: 9229: 9225: 9219: 9216: 9214: 9211: 9210: 9208: 9206: 9202: 9196: 9193: 9191: 9188: 9186: 9185:Superabundant 9183: 9181: 9178: 9176: 9173: 9171: 9168: 9166: 9163: 9161: 9158: 9156: 9153: 9151: 9148: 9146: 9143: 9141: 9138: 9136: 9133: 9131: 9128: 9126: 9123: 9121: 9118: 9116: 9113: 9111: 9108: 9106: 9103: 9101: 9098: 9096: 9093: 9091: 9088: 9087: 9085: 9083: 9079: 9075: 9071: 9067: 9062: 9058: 9048: 9045: 9043: 9040: 9038: 9035: 9033: 9030: 9028: 9025: 9023: 9020: 9018: 9015: 9013: 9010: 9008: 9005: 9003: 9000: 8998: 8995: 8993: 8990: 8989: 8986: 8982: 8977: 8973: 8963: 8960: 8958: 8955: 8953: 8950: 8948: 8945: 8944: 8941: 8937: 8932: 8928: 8918: 8915: 8913: 8910: 8908: 8905: 8903: 8900: 8898: 8895: 8893: 8890: 8888: 8885: 8883: 8880: 8878: 8875: 8873: 8870: 8868: 8865: 8863: 8860: 8858: 8855: 8853: 8850: 8848: 8845: 8843: 8840: 8838: 8835: 8833: 8830: 8828: 8825: 8823: 8820: 8819: 8816: 8809: 8805: 8787: 8784: 8782: 8779: 8777: 8774: 8773: 8771: 8767: 8764: 8762: 8761:4-dimensional 8758: 8748: 8745: 8744: 8742: 8740: 8736: 8730: 8727: 8725: 8722: 8720: 8717: 8715: 8712: 8710: 8707: 8705: 8702: 8701: 8699: 8697: 8693: 8687: 8684: 8682: 8679: 8677: 8674: 8672: 8671:Centered cube 8669: 8667: 8664: 8663: 8661: 8659: 8655: 8652: 8650: 8649:3-dimensional 8646: 8636: 8633: 8631: 8628: 8626: 8623: 8621: 8618: 8616: 8613: 8611: 8608: 8606: 8603: 8601: 8598: 8596: 8593: 8591: 8588: 8587: 8585: 8583: 8579: 8573: 8570: 8568: 8565: 8563: 8560: 8558: 8555: 8553: 8550: 8548: 8545: 8543: 8540: 8538: 8535: 8533: 8530: 8529: 8527: 8525: 8521: 8518: 8516: 8515:2-dimensional 8512: 8508: 8504: 8499: 8495: 8485: 8482: 8480: 8477: 8475: 8472: 8470: 8467: 8465: 8462: 8460: 8459:Nonhypotenuse 8457: 8456: 8453: 8446: 8442: 8432: 8429: 8427: 8424: 8422: 8419: 8417: 8414: 8412: 8409: 8408: 8405: 8398: 8394: 8384: 8381: 8379: 8376: 8374: 8371: 8369: 8366: 8364: 8361: 8359: 8356: 8354: 8351: 8349: 8346: 8345: 8342: 8337: 8332: 8328: 8318: 8315: 8313: 8310: 8308: 8305: 8303: 8300: 8298: 8295: 8294: 8291: 8284: 8280: 8270: 8267: 8265: 8262: 8260: 8257: 8255: 8252: 8250: 8247: 8245: 8242: 8240: 8237: 8236: 8233: 8228: 8222: 8218: 8208: 8205: 8203: 8200: 8198: 8197:Perfect power 8195: 8193: 8190: 8188: 8187:Seventh power 8185: 8183: 8180: 8178: 8175: 8173: 8170: 8168: 8165: 8163: 8160: 8158: 8155: 8153: 8150: 8148: 8145: 8143: 8140: 8139: 8136: 8131: 8126: 8122: 8118: 8110: 8105: 8103: 8098: 8096: 8091: 8090: 8087: 8075: 8072: 8070: 8067: 8065: 8062: 8060: 8057: 8055: 8052: 8050: 8047: 8045: 8042: 8040: 8037: 8035: 8032: 8031: 8029: 8025: 8019: 8016: 8014: 8013:Polydivisible 8011: 8009: 8006: 8004: 8001: 7999: 7996: 7994: 7991: 7990: 7988: 7985: 7981: 7975: 7972: 7970: 7967: 7964: 7960: 7957: 7955: 7952: 7951: 7949: 7946: 7942: 7936: 7933: 7931: 7928: 7926: 7923: 7921: 7918: 7916: 7915:Superabundant 7913: 7911: 7908: 7906: 7903: 7901: 7898: 7897: 7895: 7891: 7885: 7884:ErdƑs–Nicolas 7882: 7880: 7877: 7875: 7872: 7870: 7867: 7865: 7862: 7860: 7857: 7855: 7852: 7850: 7847: 7845: 7842: 7840: 7837: 7835: 7832: 7831: 7829: 7825: 7819: 7816: 7814: 7811: 7809: 7806: 7804: 7801: 7799: 7796: 7794: 7793:Perfect power 7791: 7789: 7786: 7784: 7781: 7779: 7776: 7774: 7771: 7769: 7766: 7764: 7761: 7759: 7756: 7755: 7753: 7749: 7744: 7734: 7731: 7729: 7726: 7724: 7721: 7719: 7716: 7714: 7711: 7709: 7706: 7705: 7703: 7699: 7690: 7685: 7683: 7678: 7676: 7671: 7670: 7667: 7653:on 2013-05-31 7652: 7648: 7644: 7640: 7635: 7632: 7629: 7626: 7623: 7620: 7617: 7615: 7609: 7604: 7603: 7598: 7595: 7590: 7588: 7585: 7583: 7580:David Moews: 7579: 7575: 7571: 7570: 7565: 7561: 7560: 7556: 7550: 7546: 7542: 7540:1-4020-2546-7 7536: 7532: 7527: 7526: 7519: 7516: 7512: 7509: 7505: 7501: 7497: 7492: 7487: 7483: 7479: 7478: 7473: 7468: 7465: 7464: 7460: 7453: 7449: 7444: 7440: 7436: 7432: 7428: 7424: 7420: 7415: 7412: 7408: 7407: 7402: 7401: 7396: 7386: 7384:9780824796969 7380: 7376: 7375: 7367: 7364: 7359: 7358: 7353: 7347: 7344: 7340: 7337:H. Novarese. 7334: 7331: 7326: 7322: 7318: 7314: 7310: 7306: 7299: 7296: 7291: 7287: 7283: 7279: 7275: 7271: 7264: 7261: 7256: 7252: 7248: 7244: 7240: 7236: 7232: 7228: 7221: 7218: 7213: 7211:9781118188613 7207: 7203: 7202: 7194: 7191: 7184: 7179: 7175: 7171: 7167: 7160: 7157: 7152: 7148: 7141: 7138: 7134: 7128: 7125: 7120: 7116: 7112: 7108: 7104: 7100: 7095: 7090: 7086: 7082: 7075: 7072: 7067: 7063: 7059: 7055: 7051: 7047: 7046: 7038: 7022: 7019: 7015: 7009: 7005: 6991: 6988: 6983: 6979: 6975: 6971: 6966: 6961: 6957: 6953: 6949: 6942: 6939: 6934: 6930: 6926: 6922: 6918: 6914: 6913: 6905: 6898: 6896: 6892: 6887: 6883: 6879: 6875: 6871: 6867: 6863: 6859: 6855: 6851: 6850: 6845: 6839: 6836: 6831: 6827: 6823: 6819: 6814: 6809: 6805: 6801: 6797: 6790: 6787: 6782: 6778: 6774: 6770: 6765: 6760: 6756: 6752: 6751: 6743: 6736: 6734: 6732: 6728: 6723: 6719: 6715: 6711: 6707: 6703: 6699: 6695: 6691: 6687: 6680: 6677: 6672: 6668: 6661: 6658: 6654:(6): 523-527. 6653: 6649: 6642: 6639: 6626: 6622: 6618: 6611: 6608: 6595: 6590: 6586: 6582: 6575: 6568: 6565: 6559: 6554: 6550: 6546: 6545: 6540: 6533: 6530: 6517: 6513: 6509: 6502: 6499: 6493: 6488: 6484: 6480: 6476: 6469: 6466: 6454: 6450: 6443: 6436: 6434: 6430: 6418: 6414: 6410: 6406: 6402: 6398: 6393: 6388: 6384: 6380: 6373: 6366: 6363: 6350: 6345: 6341: 6337: 6330: 6323: 6320: 6308: 6304: 6297: 6290: 6287: 6274: 6269: 6265: 6261: 6257: 6253: 6246: 6239: 6236: 6230: 6226: 6222: 6218: 6213: 6208: 6204: 6200: 6193: 6190: 6177: 6172: 6168: 6164: 6160: 6156: 6149: 6142: 6139: 6134: 6130: 6126: 6122: 6115: 6112: 6099: 6094: 6090: 6086: 6082: 6078: 6071: 6064: 6061: 6056: 6052: 6045: 6038: 6035: 6030: 6026: 6022: 6018: 6014: 6011:(in German). 6010: 6003: 6000: 5995: 5991: 5987: 5983: 5978: 5973: 5969: 5965: 5964: 5956: 5949: 5947: 5945: 5941: 5929: 5925: 5918: 5915: 5912: 5908: 5904: 5899: 5896: 5884: 5877: 5871: 5868: 5863: 5862: 5857: 5851: 5848: 5842: 5841: 5836: 5833: 5826: 5823: 5811: 5805: 5802: 5798: 5794: 5793: 5788: 5784: 5777: 5774: 5769: 5763: 5748: 5747: 5742: 5736: 5734: 5730: 5725: 5723:88-8358-537-2 5719: 5715: 5714: 5706: 5703: 5698: 5696:0-19-515799-0 5692: 5688: 5687: 5679: 5676: 5671: 5670: 5665: 5659: 5656: 5651: 5649:0-486-20430-8 5645: 5641: 5640: 5635: 5630: 5625: 5622: 5618: 5612: 5609: 5604: 5597: 5596: 5593: 5585: 5582: 5578: 5572: 5569: 5565: 5561: 5560: 5553: 5550: 5538: 5534: 5528: 5525: 5520: 5519: 5514: 5508: 5505: 5501: 5495: 5492: 5481: 5477: 5471: 5468: 5461: 5452: 5448: 5425: 5422: 5419: 5414: 5410: 5399: 5391: 5383: 5377: 5364: 5360: 5342: 5339: 5334: 5330: 5319: 5316: 5309: 5305: 5302: 5300: 5297: 5295: 5292: 5290: 5287: 5285: 5282: 5280: 5277: 5275: 5272: 5271: 5267: 5265: 5263: 5262:weird numbers 5258: 5253: 5251: 5223: 5218: 5214: 5210: 5206: 5202: 5198: 5194: 5189: 5187: 5183: 5179: 5175: 5171: 5167: 5163: 5159: 5151: 5142: 5133: 5124: 5115: 5111: 5102: 5098: 5097:Superabundant 5089: 5080: 5071: 5062: 5061:Euler diagram 5058: 5051: 5046: 5042: 5039: 5035: 5032: 5011: 5003: 4995: 4977: 4972: 4965:is less than 4964: 4960: 4945: 4942: 4937: 4933: 4925: 4906: 4903: 4898: 4894: 4885: 4882: 4879: 4875: 4866: 4862: 4858: 4853: 4849: 4848: 4846: 4842: 4825: 4822: 4819: 4815: 4811: 4808: 4805: 4801: 4797: 4794: 4791: 4787: 4783: 4780: 4777: 4773: 4769: 4766: 4763: 4759: 4755: 4752: 4749: 4745: 4741: 4733: 4718: 4715: 4710: 4706: 4703: 4700: 4694: 4689: 4685: 4682: 4679: 4676: 4673: 4670: 4667: 4661: 4656: 4653: 4648: 4643: 4640: 4635: 4630: 4627: 4622: 4617: 4614: 4609: 4604: 4601: 4596: 4591: 4588: 4583: 4578: 4575: 4570: 4565: 4562: 4552: 4551: 4549: 4533: 4530: 4527: 4521: 4513: 4509: 4500: 4496: 4492: 4489: 4488:Gallardo 2010 4485: 4482: 4481:Makowski 1962 4478: 4474: 4473: 4472: 4470: 4466: 4458:Minor results 4457: 4454: 4450: 4448: 4422: 4419: 4416: 4413: 4410: 4405: 4401: 4397: 4393: 4388: 4384: 4381: 4361: 4358: 4355: 4352: 4349: 4344: 4340: 4336: 4333: 4330: 4323: 4320: 4317: 4316: 4313: 4308: 4304: 4297: 4292: 4288: 4284: 4277: 4273: 4256: 4251: 4248: 4245: 4242: 4239: 4236: 4233: 4229: 4222: 4219: 4216: 4205: 4201: 4196: 4192: 4185: 4181: 4178: 4174: 4170: 4165: 4161: 4157: 4154: 4150: 4146: 4141: 4137: 4133: 4130: 4125: 4121: 4117: 4114: 4109: 4105: 4101: 4100: 4099: 4096: 4092: 4085: 4063: 4060: 4057: 4054: 4047: 4043: 4039: 4034: 4031: 4028: 4021: 4017: 4013: 4008: 4001: 3997: 3993: 3988: 3983: 3980: 3971: 3953: 3950: 3945: 3941: 3938: 3933: 3929: 3925: 3920: 3916: 3910: 3906: 3900: 3896: 3892: 3885: 3868: 3864: 3861: 3858: 3855: 3849: 3844: 3840: 3836: 3833: 3830: 3827: 3822: 3818: 3814: 3811: 3806: 3802: 3798: 3795: 3790: 3786: 3782: 3779: 3776: 3769: 3748: 3745: 3742: 3738: 3734: 3729: 3726: 3723: 3719: 3711: 3707: 3704: 3697: 3694: 3690: 3676: 3671: 3667: 3664: 3661: 3650: 3646: 3643: 3639: 3636: 3632: 3628: 3621: 3617: 3614: 3613: 3611: 3595: 3588: 3584: 3580: 3575: 3571: 3567: 3560: 3556: 3552: 3547: 3543: 3537: 3533: 3529: 3526: 3519: 3518: 3517: 3516: 3512: 3509: 3506: 3502: 3498: 3495: 3481: 3475: 3470: 3467: 3456: 3438: 3433: 3430: 3419: 3405: 3399: 3394: 3391: 3380: 3376: 3373: 3369: 3365: 3361: 3358: 3355: 3352: 3349: 3346: 3345: 3344: 3342: 3337: 3335: 3331: 3327: 3323: 3318: 3311: 3294: 3292: 3290: 3286: 3281: 3279: 3274: 3255: 3252:1111111000000 3251: 3247: 3238: 3234: 3230: 3225: 3221: 3217: 3212: 3208: 3204: 3199: 3195: 3191: 3186: 3182: 3178: 3173: 3169: 3165: 3160: 3156: 3148: 3143: 3139: 3129: 3125: 3121: 3114: 3110: 3106: 3101: 3097: 3093: 3088: 3084: 3080: 3075: 3071: 3067: 3062: 3058: 3052: 3047: 3043: 3033: 3029: 3025: 3018: 3014: 3010: 3005: 3001: 2997: 2992: 2988: 2982: 2977: 2973: 2963: 2959: 2955: 2948: 2944: 2940: 2935: 2931: 2925: 2920: 2916: 2903: 2899: 2878: 2872: 2869: 2864: 2860: 2851: 2848: 2845: 2841: 2831: 2810: 2807: 2802: 2798: 2789: 2786: 2783: 2779: 2768: 2747: 2744: 2739: 2735: 2726: 2723: 2720: 2716: 2695: 2634: 2619: 2615: 2608: 2605: 2600: 2596: 2588: 2584: 2581: 2578: 2575: 2572: 2567: 2560: 2557: 2552: 2548: 2541: 2535: 2532: 2527: 2523: 2513: 2510: 2507: 2502: 2499: 2494: 2490: 2485: 2475: 2456: 2452: 2448: 2443: 2439: 2435: 2430: 2426: 2422: 2419: 2416: 2411: 2407: 2403: 2398: 2394: 2390: 2385: 2381: 2377: 2375: 2365: 2362: 2359: 2356: 2353: 2350: 2347: 2344: 2341: 2338: 2335: 2332: 2329: 2326: 2324: 2315: 2312: 2307: 2303: 2294: 2290: 2286: 2284: 2279: 2270: 2266: 2262: 2257: 2253: 2249: 2244: 2240: 2236: 2231: 2227: 2223: 2218: 2214: 2210: 2205: 2201: 2197: 2192: 2188: 2184: 2179: 2175: 2171: 2169: 2159: 2156: 2153: 2150: 2147: 2144: 2141: 2138: 2135: 2132: 2129: 2126: 2123: 2120: 2118: 2109: 2106: 2101: 2097: 2088: 2084: 2080: 2078: 2073: 2064: 2060: 2056: 2051: 2047: 2043: 2038: 2034: 2030: 2025: 2021: 2017: 2015: 2005: 2002: 1999: 1996: 1993: 1990: 1987: 1984: 1981: 1978: 1975: 1972: 1969: 1966: 1964: 1955: 1952: 1947: 1943: 1934: 1930: 1926: 1924: 1919: 1910: 1906: 1902: 1897: 1893: 1889: 1887: 1877: 1874: 1871: 1868: 1865: 1862: 1859: 1856: 1853: 1850: 1847: 1844: 1841: 1838: 1836: 1827: 1824: 1819: 1815: 1806: 1802: 1798: 1796: 1791: 1784: 1781: 1778: 1775: 1772: 1769: 1766: 1764: 1755: 1752: 1747: 1743: 1734: 1730: 1726: 1724: 1719: 1707: 1693: 1690: 1684: 1680: 1677: 1674: 1668: 1644: 1640: 1637: 1634: 1628: 1619: 1600: 1596: 1593: 1588: 1584: 1571: 1553: 1550: 1547: 1543: 1522: 1519: 1514: 1510: 1501: 1482: 1479: 1474: 1470: 1443: 1440: 1435: 1431: 1422: 1419: 1416: 1412: 1402: 1400: 1396: 1376: 1371: 1363: 1362: 1361: 1344: 1341: 1336: 1332: 1323: 1320: 1317: 1313: 1304: 1299: 1297: 1293: 1274: 1271: 1266: 1262: 1253: 1250: 1247: 1243: 1234: 1230: 1214: 1211: 1206: 1202: 1178: 1175: 1170: 1166: 1157: 1154: 1151: 1147: 1136: 1134: 1129: 1115: 1112: 1107: 1103: 1083:with a prime 1070: 1067: 1062: 1058: 1033: 1030: 1025: 1021: 1012: 1011:number theory 1008: 1004: 1001:are known as 988: 985: 980: 976: 966: 949: 946: 943: 940: 937: 934: 928: 925: 920: 916: 907: 903: 898: 896: 891: 888: 885: 878: 875: 872: 869: 866: 863: 857: 854: 849: 845: 836: 832: 827: 825: 820: 817: 814: 807: 804: 801: 798: 795: 792: 786: 783: 778: 774: 765: 761: 756: 754: 749: 746: 743: 736: 733: 730: 727: 724: 721: 715: 712: 707: 703: 694: 690: 685: 683: 678: 675: 672: 660: 640: 634: 631: 626: 622: 613: 610: 607: 603: 593: 591: 590: 573: 570: 565: 561: 537: 534: 529: 525: 516: 513: 510: 506: 497: 491: 476: 468: 466: 464: 460: 456: 452: 448: 444: 424: 421: 416: 412: 388: 385: 380: 376: 367: 364: 361: 357: 346: 344: 340: 332: 330: 327: 325: 321: 317: 301: 281: 278: 273: 269: 261: 245: 225: 221: 214: 211: 208: 202: 194: 190: 186: 182: 172: 171: 164: 162: 144: 140: 119: 116: 113: 107: 99: 95: 86: 81: 79: 75: 71: 67: 62: 60: 56: 52: 48: 47:number theory 39: 33: 19: 9741:Transposable 9605:Narcissistic 9512:Digital root 9432:Super-Poulet 9392:Jordan–PĂłlya 9341:prime factor 9283: 9246:Noncototient 9213:Almost prime 9195:Superperfect 9170:Refactorable 9165:Quasiperfect 9149: 9140:Hyperperfect 8981:Pseudoprimes 8952:Wall–Sun–Sun 8887:Ordered Bell 8857:Fuss–Catalan 8769:non-centered 8719:Dodecahedral 8696:non-centered 8582:non-centered 8484:Wolstenholme 8229:× 2 ± 1 8226: 8225:Of the form 8192:Eighth power 8172:Fourth power 8074:Superperfect 8069:Refactorable 7864:Superperfect 7859:Hyperperfect 7844:Quasiperfect 7833: 7728:Prime factor 7655:. Retrieved 7651:the original 7642: 7600: 7567: 7524: 7514: 7507: 7481: 7475: 7451: 7447: 7422: 7418: 7404: 7373: 7366: 7356: 7346: 7338: 7333: 7308: 7304: 7298: 7273: 7269: 7263: 7230: 7226: 7220: 7200: 7193: 7173: 7169: 7159: 7150: 7146: 7140: 7132: 7127: 7087:(1): 15–21. 7084: 7080: 7074: 7052:(1): 25–28. 7049: 7043: 6990: 6958:(1): 13–15. 6955: 6951: 6941: 6919:(1): 70–76. 6916: 6910: 6853: 6847: 6838: 6803: 6799: 6789: 6754: 6748: 6692:(1): 52–53. 6689: 6685: 6679: 6670: 6666: 6660: 6651: 6647: 6641: 6629:. Retrieved 6624: 6620: 6610: 6598:. Retrieved 6584: 6580: 6567: 6548: 6542: 6532: 6520:. Retrieved 6515: 6511: 6501: 6482: 6478: 6468: 6456:. Retrieved 6452: 6448: 6420:. Retrieved 6392:math/0602485 6382: 6378: 6365: 6353:. Retrieved 6339: 6335: 6322: 6310:. Retrieved 6306: 6302: 6289: 6277:. Retrieved 6255: 6251: 6238: 6202: 6198: 6192: 6180:. Retrieved 6158: 6154: 6141: 6124: 6120: 6114: 6102:. Retrieved 6080: 6076: 6063: 6054: 6050: 6037: 6012: 6008: 6002: 5967: 5961: 5933:10 September 5931:. Retrieved 5927: 5917: 5898: 5886:. Retrieved 5882: 5870: 5860: 5850: 5838: 5825: 5814:. Retrieved 5810:"GIMPS Home" 5804: 5790: 5776: 5750:. Retrieved 5744: 5712: 5705: 5685: 5678: 5668: 5658: 5638: 5624: 5616: 5611: 5602: 5595: 5591: 5584: 5571: 5557: 5552: 5540:. Retrieved 5536: 5527: 5517: 5507: 5494: 5483:. Retrieved 5479: 5470: 5397: 5389: 5381: 5362: 5318: 5254: 5216: 5212: 5208: 5204: 5200: 5190: 5169: 5155: 5131: 5038:digital root 4993: 4962: 4924:Fermat prime 4844: 4547: 4498: 4476: 4461: 4452: 4444: 4318: 4311: 4306: 4302: 4295: 4286: 4282: 4275: 4203: 4199: 4194: 4190: 4183: 4176: 4172: 4168: 4163: 4159: 4152: 4139: 4135: 4123: 4119: 4107: 4103: 4094: 4090: 4083: 4081: 3692: 3648: 3637: 3630: 3626: 3619: 3615: 3510: 3504: 3500: 3496: 3378: 3371: 3367: 3363: 3359: 3353: 3347: 3340: 3338: 3314: 3282: 3275: 2904: 2897: 2832: 2694:digital root 2635: 2476: 1708: 1403: 1380: 1300: 1130: 967: 659:prime number 594: 587: 498:proved that 494: 336: 328: 188: 184: 180: 169: 165: 82: 63: 50: 44: 9762:Extravagant 9757:Equidigital 9712:permutation 9671:Palindromic 9645:Automorphic 9543:Sum-product 9522:Sum-product 9477:Persistence 9372:ErdƑs–Woods 9294:Untouchable 9175:Semiperfect 9125:Hemiperfect 8786:Tesseractic 8724:Icosahedral 8704:Tetrahedral 8635:Dodecagonal 8336:Recursively 8207:Prime power 8182:Sixth power 8177:Fifth power 8157:Power of 10 8115:Classes of 7998:Extravagant 7993:Equidigital 7954:Untouchable 7874:Semiperfect 7854:Hemiperfect 7783:Square-free 7647:Brady Haran 7643:Numberphile 7513:Riesel, H. 6600:29 November 6015:: 202–211. 5883:Harvard.edu 5193:fixed point 5156:The sum of 5045:square-free 4495:reciprocals 4465:Richard Guy 4206:twos, then 3695:exceeds 10. 3651:is at most 3644:4) (Euler). 1391:2 × (2 − 1) 455:City of God 260:of the form 258:is a prime 85:aliquot sum 10023:Categories 9974:Graphemics 9847:Pernicious 9701:Undulating 9676:Pandigital 9650:Trimorphic 9251:Nontotient 9100:Arithmetic 8714:Octahedral 8615:Heptagonal 8605:Pentagonal 8590:Triangular 8431:SierpiƄski 8353:Jacobsthal 8152:Power of 3 8147:Power of 2 8034:Arithmetic 8027:Other sets 7986:-dependent 7657:2013-04-02 7549:1079.11001 7270:Arch. Math 7170:Elem. Math 7147:Elem. Math 7094:1706.09341 6673:: 896–904. 6631:7 December 6594:2303.11974 6312:6 December 6212:1810.11734 5994:1263.11005 5816:2022-07-21 5485:2024-03-21 5462:References 5378:—that is, 5220:, and the 5174:numerology 2702:1 + 9 = 10 1535:) and the 1133:Nicomachus 586:is prime ( 473:See also: 343:Nicomachus 9731:Parasitic 9580:Factorion 9507:Digit sum 9499:Digit sum 9317:Fortunate 9304:Primorial 9218:Semiprime 9155:Practical 9120:Descartes 9115:Deficient 9105:Betrothed 8947:Wieferich 8776:Pentatope 8739:pyramidal 8630:Decagonal 8625:Nonagonal 8620:Octagonal 8610:Hexagonal 8469:Practical 8416:Congruent 8348:Fibonacci 8312:Loeschian 8064:Descartes 8039:Deficient 7974:Betrothed 7879:Practical 7768:Semiprime 7763:Composite 7602:MathWorld 7574:EMS Press 7439:115983363 7325:122353640 7305:Math. Ann 7290:122525522 7255:125545112 7153:(5): 109. 7119:119175632 7111:1730-6302 7058:0015-0517 7023:β 7010:α 6974:1088-6826 6925:0015-0517 6886:122452828 6870:1435-5345 6822:1446-8107 6773:0025-5718 6722:121251041 6706:1420-8938 6518:: A14–A22 6355:13 August 6057:(4): 244. 6029:120754476 5986:0025-5718 5840:MathWorld 5420:− 5340:− 5162:deficient 5150:Deficient 5141:Composite 5043:The only 4883:− 4704:⋅ 4510:σ 4447:Sylvester 4445:In 1888, 4334:≤ 4257:α 4243:≤ 4237:≤ 4220:− 4202:ones and 4147:3) or 2 ( 4061:⁡ 4032:⋯ 3926:⋯ 3862:− 3850:≥ 3831:⋯ 3777:α 3735:− 3665:− 3568:⋯ 3538:α 3126:111110000 2870:− 2849:− 2808:− 2787:− 2745:− 2724:− 2706:1 + 0 = 1 2606:− 2585:× 2542:× 2533:− 2500:− 2420:⋯ 2348:⋯ 2313:− 2142:⋯ 2107:− 1988:⋯ 1953:− 1825:− 1753:− 1691:− 1638:− 1551:− 1520:− 1480:− 1441:− 1420:− 1395:not known 1342:− 1321:− 1272:− 1251:− 1212:− 1176:− 1155:− 1113:− 1068:− 1031:− 986:− 941:× 926:− 870:× 855:− 799:× 784:− 728:× 713:− 632:− 611:− 571:− 535:− 514:− 449:, and by 422:− 386:− 365:− 279:− 168:Euclid's 141:σ 96:σ 9803:Friedman 9736:Primeval 9681:Repdigit 9638:-related 9585:Kaprekar 9559:Meertens 9482:Additive 9469:dynamics 9377:Friendly 9289:Sociable 9279:Amicable 9090:Abundant 9070:dynamics 8892:Schröder 8882:Narayana 8852:Eulerian 8842:Delannoy 8837:Dedekind 8658:centered 8524:centered 8411:Amenable 8368:Narayana 8358:Leonardo 8254:Mersenne 8202:Powerful 8142:Achilles 8049:Solitary 8044:Friendly 7969:Sociable 7959:Amicable 7947:-related 7900:Abundant 7798:Achilles 7788:Powerful 7701:Overview 7454:: 69–72. 7406:Elements 7403:Euclid, 7354:(1919). 6581:Integers 6522:23 March 6512:Integers 6458:7 August 6449:Integers 6422:30 March 6303:Integers 6279:30 March 6229:62885986 6182:30 March 6104:30 March 5907:Archived 5858:(1919). 5762:cite web 5666:(1919). 5636:(1925). 5515:(1919). 5480:oeis.org 5268:See also 5182:sociable 5178:amicable 5166:abundant 5070:Abundant 5029:, using 4992:, where 4449:stated: 4301:= ... = 4118:Not all 4102:Not all 3350:> 10. 2280:33550336 589:Elements 170:Elements 59:divisors 9976:related 9940:related 9904:related 9902:Sorting 9787:Vampire 9772:Harshad 9714:related 9686:Repunit 9600:Lychrel 9575:Dudeney 9427:StĂžrmer 9422:Sphenic 9407:Regular 9345:divisor 9284:Perfect 9180:Sublime 9150:Perfect 8877:Motzkin 8832:Catalan 8373:Padovan 8307:Leyland 8302:Idoneal 8297:Hilbert 8269:Woodall 8054:Sublime 8008:Harshad 7834:Perfect 7818:Unusual 7808:Regular 7778:Sphenic 7713:Divisor 7627:(GIMPS) 7576:, 2001 7500:2005530 7397:Sources 7247:3619053 7066:0354538 6982:0292740 6933:0786364 6878:0044579 6830:0869751 6781:2904601 6714:0258723 6627:: 23–30 6417:2767519 6397:Bibcode 6260:Bibcode 6163:Bibcode 6085:Bibcode 5888:16 June 5752:28 July 5451:A002515 5449::  5195:of the 5170:perfect 5148:  5139:  5132:Perfect 5130:  5121:  5108:  5095:  5086:  5077:  5068:  4315:, then 4134:If all 3618:,  3612:where: 3503:, then 1373:in the 1370:A000043 333:History 181:perfect 159:is the 9842:Odious 9767:Frugal 9721:Cyclic 9710:Digit- 9417:Smooth 9402:Pronic 9362:Cyclic 9339:Other 9312:Euclid 8962:Wilson 8936:Primes 8595:Square 8464:Polite 8426:Riesel 8421:Knödel 8383:Perrin 8264:Thabit 8249:Fermat 8239:Cullen 8162:Square 8130:Powers 8003:Frugal 7963:Triple 7803:Smooth 7773:Pronic 7547:  7537:  7498:  7437:  7381:  7323:  7288:  7253:  7245:  7208:  7117:  7109:  7064:  7056:  6980:  6972:  6931:  6923:  6884:  6876:  6868:  6828:  6820:  6779:  6771:  6720:  6712:  6704:  6415:  6227:  6027:  5992:  5984:  5720:  5693:  5646:  5146:  5137:  5128:  5119:  5106:  5093:  5084:  5075:  5066:  4838:, etc. 2704:, and 2658:= 8128 1194:where 1131:While 496:Euclid 447:Origen 404:where 193:Euclid 132:where 9883:Prime 9878:Lucky 9867:sieve 9796:Other 9782:Smith 9662:Digit 9620:Happy 9595:Keith 9568:Other 9412:Rough 9382:Giuga 8847:Euler 8709:Cubic 8363:Lucas 8259:Proth 8018:Smith 7935:Weird 7813:Rough 7758:Prime 7533:–98. 7496:JSTOR 7435:S2CID 7321:S2CID 7286:S2CID 7251:S2CID 7243:JSTOR 7115:S2CID 7089:arXiv 7040:(PDF) 6907:(PDF) 6882:S2CID 6745:(PDF) 6718:S2CID 6589:arXiv 6577:(PDF) 6445:(PDF) 6413:S2CID 6387:arXiv 6375:(PDF) 6332:(PDF) 6299:(PDF) 6248:(PDF) 6225:S2CID 6207:arXiv 6151:(PDF) 6073:(PDF) 6047:(PDF) 6025:S2CID 5958:(PDF) 5879:(PDF) 5599:(PDF) 5542:9 May 5374:is a 5310:Notes 5123:Weird 5112:and 5099:and 3287:(cf. 3030:11100 2682:= 903 2650:= 496 1303:GIMPS 950:8128. 653:with 347:every 187:, or 185:ideal 53:is a 9837:Evil 9517:Self 9467:and 9357:Blum 9068:and 8872:Lobb 8827:Cake 8822:Bell 8572:Star 8479:Ulam 8378:Pell 8167:Cube 7984:Base 7611:OEIS 7535:ISBN 7452:1937 7423:1941 7379:ISBN 7206:ISBN 7107:ISSN 7054:ISSN 6970:ISSN 6921:ISSN 6866:ISSN 6818:ISSN 6769:ISSN 6702:ISSN 6633:2018 6602:2023 6524:2021 6460:2021 6424:2011 6357:2015 6314:2021 6281:2011 6184:2011 6106:2011 5982:ISSN 5935:2020 5890:2023 5768:link 5754:2024 5718:ISBN 5691:ISBN 5644:ISBN 5544:2018 5447:OEIS 5215:) − 5207:) = 4493:The 4385:< 4374:and 4182:If ( 4055:< 3939:< 3708:< 3140:8128 2688:2730 2674:= 55 2642:= 28 2366:8191 2360:8190 2354:8189 2074:8128 1616:-th 1568:-th 1498:-th 1375:OEIS 1360:for 78:8128 76:and 49:, a 9955:Ban 9343:or 8862:Lah 7545:Zbl 7486:doi 7427:doi 7313:doi 7309:131 7278:doi 7235:doi 7178:doi 7099:doi 7085:156 6960:doi 6858:doi 6854:188 6808:doi 6759:doi 6694:doi 6553:doi 6487:doi 6405:doi 6344:doi 6268:doi 6217:doi 6171:doi 6129:doi 6093:doi 6017:doi 5990:Zbl 5972:doi 5556:In 5400:+ 1 5392:+ 1 5384:+ 1 5359:mod 4550:): 4467:'s 4293:If 4149:mod 4145:mod 4131:5). 4129:mod 4115:3). 4113:mod 3865:224 3642:mod 3291:). 3044:496 2960:110 2900:− 1 2769:all 2666:= 3 2656:127 2453:127 2440:125 2427:123 2160:127 2154:126 2148:125 1920:496 1706:): 1137:all 944:127 879:496 191:). 74:496 45:In 10025:: 7645:. 7641:. 7599:. 7572:, 7566:, 7543:. 7531:15 7494:. 7482:27 7480:. 7474:. 7450:. 7433:. 7421:. 7319:. 7307:. 7284:. 7272:. 7249:. 7241:. 7231:83 7229:. 7174:65 7172:. 7168:. 7151:17 7149:. 7113:. 7105:. 7097:. 7083:. 7062:MR 7060:. 7050:13 7048:. 7042:. 6978:MR 6976:. 6968:. 6956:32 6954:. 6950:. 6929:MR 6927:. 6917:23 6915:. 6909:. 6894:^ 6880:. 6874:MR 6872:. 6864:. 6852:. 6826:MR 6824:. 6816:. 6804:42 6802:. 6798:. 6777:MR 6775:. 6767:. 6755:81 6753:. 6747:. 6730:^ 6716:. 6710:MR 6708:. 6700:. 6690:21 6688:. 6671:14 6669:. 6652:16 6650:. 6625:16 6623:. 6619:. 6587:. 6585:23 6583:. 6579:. 6549:83 6547:. 6541:. 6514:. 6510:. 6483:89 6481:. 6477:. 6453:21 6451:. 6447:. 6432:^ 6411:. 6403:. 6395:. 6383:76 6381:. 6377:. 6340:84 6338:. 6334:. 6307:21 6305:. 6301:. 6266:. 6256:69 6254:. 6250:. 6223:. 6215:. 6203:15 6201:. 6169:. 6159:68 6157:. 6153:. 6123:. 6091:. 6081:77 6079:. 6075:. 6055:35 6053:. 6049:. 6023:. 6013:52 5988:. 5980:. 5968:81 5966:. 5960:. 5943:^ 5926:. 5905:. 5881:. 5837:. 5795:, 5789:, 5785:, 5764:}} 5760:{{ 5743:. 5732:^ 5601:. 5535:. 5478:. 5357:1 5264:. 5255:A 5252:. 5188:. 4764:14 4750:28 4490:). 4483:). 4471:: 4310:= 4098:. 4058:ln 3954:26 3951:17 3869:37 3856:99 3280:. 3187:10 3174:11 3161:12 3144:10 3048:10 2978:10 2974:28 2921:10 2830:. 2700:, 2684:, 2680:42 2676:, 2672:10 2668:, 2652:, 2648:31 2644:, 2308:13 2295:12 2267:15 2254:13 2241:11 2006:31 2000:30 1994:29 1792:28 1377:). 1298:. 938:64 873:31 867:16 808:28 657:a 326:. 183:, 163:. 80:. 72:, 70:28 68:, 8227:a 8108:e 8101:t 8094:v 7965:) 7961:( 7688:e 7681:t 7674:v 7660:. 7605:. 7551:. 7502:. 7488:: 7441:. 7429:: 7389:. 7387:. 7327:. 7315:: 7292:. 7280:: 7274:6 7257:. 7237:: 7215:. 7188:. 7186:. 7180:: 7121:. 7101:: 7091:: 7068:. 7037:" 7020:2 7016:M 7006:p 6984:. 6962:: 6935:. 6888:. 6860:: 6832:. 6810:: 6783:. 6761:: 6724:. 6696:: 6635:. 6604:. 6591:: 6561:. 6555:: 6526:. 6516:3 6495:. 6489:: 6462:. 6426:. 6407:: 6399:: 6389:: 6359:. 6346:: 6316:. 6283:. 6270:: 6262:: 6233:. 6231:. 6219:: 6209:: 6186:. 6173:: 6165:: 6135:. 6131:: 6125:8 6108:. 6095:: 6087:: 6031:. 6019:: 5996:. 5974:: 5937:. 5892:. 5843:. 5819:. 5770:) 5756:. 5726:. 5699:. 5652:. 5605:. 5546:. 5502:. 5488:. 5454:. 5441:p 5426:, 5423:1 5415:p 5411:2 5398:p 5396:2 5390:p 5388:2 5382:p 5380:2 5372:p 5363:p 5361:2 5343:1 5335:p 5331:2 5234:S 5217:n 5213:n 5211:( 5209:σ 5205:n 5203:( 5201:s 5033:. 5017:) 5012:n 5007:( 5004:o 4994:c 4978:n 4973:c 4963:n 4946:1 4943:+ 4938:n 4934:2 4910:) 4907:1 4904:+ 4899:n 4895:2 4891:( 4886:1 4880:n 4876:2 4854:. 4845:N 4826:2 4823:= 4820:1 4816:/ 4812:1 4809:+ 4806:2 4802:/ 4798:1 4795:+ 4792:4 4788:/ 4784:1 4781:+ 4778:7 4774:/ 4770:1 4767:+ 4760:/ 4756:1 4753:+ 4746:/ 4742:1 4731:; 4719:2 4716:= 4711:6 4707:6 4701:2 4695:= 4690:6 4686:6 4683:+ 4680:3 4677:+ 4674:2 4671:+ 4668:1 4662:= 4657:6 4654:6 4649:+ 4644:6 4641:3 4636:+ 4631:6 4628:2 4623:+ 4618:6 4615:1 4610:= 4605:1 4602:1 4597:+ 4592:2 4589:1 4584:+ 4579:3 4576:1 4571:+ 4566:6 4563:1 4548:n 4534:n 4531:2 4528:= 4525:) 4522:n 4519:( 4514:1 4499:N 4477:n 4439:. 4423:3 4420:+ 4417:e 4414:8 4411:+ 4406:2 4402:e 4398:2 4394:4 4389:2 4382:N 4362:2 4359:+ 4356:e 4353:8 4350:+ 4345:2 4341:e 4337:2 4331:k 4319:e 4312:e 4307:k 4303:e 4299:1 4296:e 4287:k 4283:e 4279:1 4276:e 4274:( 4271:. 4252:+ 4249:t 4246:2 4240:u 4234:4 4230:/ 4226:) 4223:1 4217:t 4214:( 4204:u 4200:t 4195:k 4191:e 4187:1 4184:e 4179:. 4177:S 4173:N 4169:S 4164:i 4160:e 4153:N 4140:i 4136:e 4124:i 4120:e 4108:i 4104:e 4095:k 4091:e 4087:1 4084:e 4076:. 4064:2 4048:k 4044:p 4040:1 4035:+ 4029:+ 4022:2 4018:p 4014:1 4009:+ 4002:1 3998:p 3994:1 3989:+ 3984:q 3981:1 3969:. 3946:N 3942:2 3934:k 3930:p 3921:3 3917:p 3911:2 3907:p 3901:1 3897:p 3893:q 3883:. 3859:k 3845:k 3841:e 3837:2 3834:+ 3828:+ 3823:3 3819:e 3815:2 3812:+ 3807:2 3803:e 3799:2 3796:+ 3791:1 3787:e 3783:2 3780:+ 3754:) 3749:1 3746:+ 3743:k 3739:2 3730:1 3727:+ 3724:k 3720:4 3716:( 3712:2 3705:N 3693:n 3677:. 3672:2 3668:1 3662:k 3649:N 3638:q 3631:k 3627:p 3623:1 3620:p 3616:q 3596:, 3589:k 3585:e 3581:2 3576:k 3572:p 3561:1 3557:e 3553:2 3548:1 3544:p 3534:q 3530:= 3527:N 3511:N 3505:N 3501:N 3497:N 3482:. 3476:6 3471:N 3468:2 3454:. 3439:5 3434:N 3431:2 3406:. 3400:3 3395:N 3392:3 3379:N 3372:N 3368:N 3364:N 3360:N 3354:N 3348:N 3341:N 3303:: 3256:2 3248:= 3239:6 3235:2 3231:+ 3226:7 3222:2 3218:+ 3213:8 3209:2 3205:+ 3200:9 3196:2 3192:+ 3183:2 3179:+ 3170:2 3166:+ 3157:2 3149:= 3130:2 3122:= 3115:4 3111:2 3107:+ 3102:5 3098:2 3094:+ 3089:6 3085:2 3081:+ 3076:7 3072:2 3068:+ 3063:8 3059:2 3053:= 3034:2 3026:= 3019:2 3015:2 3011:+ 3006:3 3002:2 2998:+ 2993:4 2989:2 2983:= 2964:2 2956:= 2949:1 2945:2 2941:+ 2936:2 2932:2 2926:= 2917:6 2898:p 2893:p 2879:, 2876:) 2873:1 2865:p 2861:2 2857:( 2852:1 2846:p 2842:2 2828:m 2814:) 2811:1 2803:m 2799:2 2795:( 2790:1 2784:m 2780:2 2765:p 2751:) 2748:1 2740:p 2736:2 2732:( 2727:1 2721:p 2717:2 2686:T 2678:T 2670:T 2664:2 2662:T 2654:T 2646:T 2640:7 2638:T 2620:3 2616:/ 2612:) 2609:2 2601:p 2597:2 2593:( 2589:T 2582:9 2579:+ 2576:1 2573:= 2568:2 2564:) 2561:1 2558:+ 2553:p 2549:2 2545:( 2539:) 2536:2 2528:p 2524:2 2520:( 2514:+ 2511:1 2508:= 2503:1 2495:p 2491:2 2486:T 2457:3 2449:+ 2444:3 2436:+ 2431:3 2423:+ 2417:+ 2412:3 2408:5 2404:+ 2399:3 2395:3 2391:+ 2386:3 2382:1 2378:= 2363:+ 2357:+ 2351:+ 2345:+ 2342:3 2339:+ 2336:2 2333:+ 2330:1 2327:= 2319:) 2316:1 2304:2 2300:( 2291:2 2287:= 2271:3 2263:+ 2258:3 2250:+ 2245:3 2237:+ 2232:3 2228:9 2224:+ 2219:3 2215:7 2211:+ 2206:3 2202:5 2198:+ 2193:3 2189:3 2185:+ 2180:3 2176:1 2172:= 2157:+ 2151:+ 2145:+ 2139:+ 2136:3 2133:+ 2130:2 2127:+ 2124:1 2121:= 2113:) 2110:1 2102:7 2098:2 2094:( 2089:6 2085:2 2081:= 2065:3 2061:7 2057:+ 2052:3 2048:5 2044:+ 2039:3 2035:3 2031:+ 2026:3 2022:1 2018:= 2003:+ 1997:+ 1991:+ 1985:+ 1982:3 1979:+ 1976:2 1973:+ 1970:1 1967:= 1959:) 1956:1 1948:5 1944:2 1940:( 1935:4 1931:2 1927:= 1911:3 1907:3 1903:+ 1898:3 1894:1 1890:= 1878:7 1875:+ 1872:6 1869:+ 1866:5 1863:+ 1860:4 1857:+ 1854:3 1851:+ 1848:2 1845:+ 1842:1 1839:= 1831:) 1828:1 1820:3 1816:2 1812:( 1807:2 1803:2 1799:= 1785:, 1782:3 1779:+ 1776:2 1773:+ 1770:1 1767:= 1759:) 1756:1 1748:2 1744:2 1740:( 1735:1 1731:2 1727:= 1720:6 1694:1 1685:2 1681:1 1678:+ 1675:p 1669:2 1645:2 1641:1 1635:p 1629:2 1601:3 1597:1 1594:+ 1589:p 1585:2 1554:1 1548:p 1544:2 1523:1 1515:p 1511:2 1486:) 1483:1 1475:p 1471:2 1467:( 1447:) 1444:1 1436:p 1432:2 1428:( 1423:1 1417:p 1413:2 1387:p 1383:p 1365:p 1348:) 1345:1 1337:p 1333:2 1329:( 1324:1 1318:p 1314:2 1278:) 1275:1 1267:p 1263:2 1259:( 1254:1 1248:p 1244:2 1215:1 1207:n 1203:2 1182:) 1179:1 1171:n 1167:2 1163:( 1158:1 1152:n 1148:2 1116:1 1108:p 1104:2 1093:p 1085:p 1071:1 1063:p 1059:2 1048:p 1034:1 1026:p 1022:2 989:1 981:p 977:2 947:= 935:= 932:) 929:1 921:7 917:2 913:( 908:6 904:2 899:: 892:7 889:= 886:p 876:= 864:= 861:) 858:1 850:5 846:2 842:( 837:4 833:2 828:: 821:5 818:= 815:p 805:= 802:7 796:4 793:= 790:) 787:1 779:3 775:2 771:( 766:2 762:2 757:: 750:3 747:= 744:p 737:6 734:= 731:3 725:2 722:= 719:) 716:1 708:2 704:2 700:( 695:1 691:2 686:: 679:2 676:= 673:p 655:p 641:, 638:) 635:1 627:p 623:2 619:( 614:1 608:p 604:2 574:1 566:p 562:2 541:) 538:1 530:p 526:2 522:( 517:1 511:p 507:2 483:: 439:n 425:1 417:n 413:2 392:) 389:1 381:n 377:2 373:( 368:1 362:n 358:2 302:p 282:1 274:p 270:2 246:q 226:2 222:/ 218:) 215:1 212:+ 209:q 206:( 203:q 179:( 145:1 120:n 117:2 114:= 111:) 108:n 105:( 100:1 66:6 34:. 20:)

Index

Perfect numbers
Perfect Number (film)

number theory
positive integer
divisors
6
28
496
8128
aliquot sum
sum-of-divisors function
Euclid's Elements
Euclid
of the form
Mersenne prime
Leonhard Euler
Euclid–Euler theorem
Greek mathematics
Nicomachus
Philo of Alexandria
Origen
Didymus the Blind
City of God
Ismail ibn Fallƫs
Pietro Cataldi
Euclid–Euler theorem
(more unsolved problems in mathematics)
Euclid
Elements

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.

↑