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18997000660 = 225111944310259
BaseRepresentation
bin10001101100010011…
…110011100111010100
31211000221012121211001
4101230103303213110
5302401213010120
612421015353044
71241522561401
oct215423634724
954027177731
1018997000660
118069347850
123822082784
131a3995a4c1
14cc2dd72a8
15762b95e0a
hex46c4f39d4

18997000660 has 96 divisors (see below), whose sum is σ = 45918835200. Its totient is φ = 6529011840.

The previous prime is 18997000643. The next prime is 18997000669. The reversal of 18997000660 is 6600079981.

18997000660 is a nontrivial binomial coefficient, being equal to C(194921, 2).

It is a self number, because there is not a number n which added to its sum of digits gives 18997000660.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18997000669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1846611 + ... + 1856869.

It is an arithmetic number, because the mean of its divisors is an integer number (478321200).

Almost surely, 218997000660 is an apocalyptic number.

18997000660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18997000660 is the 194920-th triangular number.

18997000660 is the 64974-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18997000660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22959417600).

18997000660 is an abundant number, since it is smaller than the sum of its proper divisors (26921834540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18997000660 is a wasteful number, since it uses less digits than its factorization.

18997000660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10741 (or 10739 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 46.

The spelling of 18997000660 in words is "eighteen billion, nine hundred ninety-seven million, six hundred sixty", and thus it is an aban number.

Divisors: 1 2 4 5 10 11 19 20 22 38 44 55 76 95 110 190 209 220 380 418 443 836 886 1045 1772 2090 2215 4180 4430 4873 8417 8860 9746 10259 16834 19492 20518 24365 33668 41036 42085 48730 51295 84170 92587 97460 102590 112849 168340 185174 194921 205180 225698 370348 389842 451396 462935 564245 779684 925870 974605 1128490 1851740 1949210 2144131 2256980 3898420 4288262 4544737 8576524 9089474 10720655 18178948 21441310 22723685 42882620 45447370 49992107 86350003 90894740 99984214 172700006 199968428 249960535 345400012 431750015 499921070 863500030 949850033 999842140 1727000060 1899700066 3799400132 4749250165 9498500330 18997000660