21691966604260 has 12 divisors (see below), whose sum is σ = 45553129868988. Its totient is φ = 8676786641696.

The previous prime is 21691966604179. The next prime is 21691966604291. The reversal of 21691966604260 is 6240666919612.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 7693877678656 + 13998088925604 = 2773784^2 + 3741402^2 .

It is a super-2 number, since 2×21691966604260² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21691966604195 and 21691966604204.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 542299165087 + ... + 542299165126.

It is an arithmetic number, because the mean of its divisors is an integer number (3796094155749).

Almost surely, 2^{21691966604260} is an apocalyptic number.

21691966604260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21691966604260 is an abundant number, since it is smaller than the sum of its proper divisors (23861163264728).

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

21691966604260 is a wasteful number, since it uses less digits than its factorization.

21691966604260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1084598330222 (or 1084598330220 counting only the distinct ones).

The product of its (nonzero) digits is 10077696, while the sum is 58.

The spelling of 21691966604260 in words is "twenty-one trillion, six hundred ninety-one billion, nine hundred sixty-six million, six hundred four thousand, two hundred sixty".