21317552631 has 6 divisors (see below), whose sum is σ = 30792020480. Its totient is φ = 14211701748.

The previous prime is 21317552563. The next prime is 21317552647. The reversal of 21317552631 is 13625571312.

21317552631 is a `hidden beast` number, since 2 + 1 + 3 + 17 + 5 + 5 + 2 + 631 = 666.

It is not a de Polignac number, because 21317552631 - 2¹⁵ = 21317519863 is a prime.

It is a super-2 number, since 2×21317552631² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317552651) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1184308471 + ... + 1184308488.

Almost surely, 2^21317552631 is an apocalyptic number.

21317552631 is a deficient number, since it is larger than the sum of its proper divisors (9474467849).

21317552631 is a wasteful number, since it uses less digits than its factorization.

21317552631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2368616965 (or 2368616962 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The spelling of 21317552631 in words is "twenty-one billion, three hundred seventeen million, five hundred fifty-two thousand, six hundred thirty-one".