31868000781 has 32 divisors (see below), whose sum is σ = 45407485440. Its totient is φ = 19823143104.

The previous prime is 31868000761. The next prime is 31868000789. The reversal of 31868000781 is 18700086813.

It is not a de Polignac number, because 31868000781 - 2¹¹ = 31867998733 is a prime.

It is a super-2 number, since 2×31868000781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31868000789) 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, 1040026 + ... + 1070228.

It is an arithmetic number, because the mean of its divisors is an integer number (1418983920).

Almost surely, 2^31868000781 is an apocalyptic number.

31868000781 is the 112904-th centered pentagonal number.

It is an amenable number.

31868000781 is a deficient number, since it is larger than the sum of its proper divisors (13539484659).

31868000781 is a wasteful number, since it uses less digits than its factorization.

31868000781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30505.

The product of its (nonzero) digits is 64512, while the sum is 42.

The spelling of 31868000781 in words is "thirty-one billion, eight hundred sixty-eight million, seven hundred eighty-one", and thus it is an aban number.