31688505861 has 16 divisors (see below), whose sum is σ = 43289069760. Its totient is φ = 20611260800.

The previous prime is 31688505859. The next prime is 31688505887. The reversal of 31688505861 is 16850588613.

It is a cyclic number.

It is not a de Polignac number, because 31688505861 - 2¹ = 31688505859 is a prime.

It is a super-2 number, since 2×31688505861² (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 (31688505661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 528240 + ... + 585161.

It is an arithmetic number, because the mean of its divisors is an integer number (2705566860).

Almost surely, 2^31688505861 is an apocalyptic number.

It is an amenable number.

31688505861 is a deficient number, since it is larger than the sum of its proper divisors (11600563899).

31688505861 is a wasteful number, since it uses less digits than its factorization.

31688505861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1113636.

The product of its (nonzero) digits is 1382400, while the sum is 51.

The spelling of 31688505861 in words is "thirty-one billion, six hundred eighty-eight million, five hundred five thousand, eight hundred sixty-one".