31688505808 has 20 divisors (see below), whose sum is σ = 62554905828. Its totient is φ = 15545304320.

The previous prime is 31688505781. The next prime is 31688505817. The reversal of 31688505808 is 80850588613.

It can be written as a sum of positive squares in 2 ways, for example, as 15593016384 + 16095489424 = 124872^2 + 126868^2 .

It is a super-2 number, since 2×31688505808² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

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, 18683413 + ... + 18685108.

Almost surely, 2^31688505808 is an apocalyptic number.

It is an amenable number.

31688505808 is a deficient number, since it is larger than the sum of its proper divisors (30866400020).

31688505808 is a wasteful number, since it uses less digits than its factorization.

31688505808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37368582 (or 37368576 counting only the distinct ones).

The product of its (nonzero) digits is 1843200, while the sum is 52.

The spelling of 31688505808 in words is "thirty-one billion, six hundred eighty-eight million, five hundred five thousand, eight hundred eight".