30688931 has 24 divisors (see below), whose sum is σ = 39215904. Its totient is φ = 23385600.

The previous prime is 30688913. The next prime is 30688937. The reversal of 30688931 is 13988603.

30688931 = 868² + 869² + ... + 906².

It is a de Polignac number, because none of the positive numbers 2^k-30688931 is a prime.

It is a super-2 number, since 2×30688931² = 1883620971845522, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (30688937) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76331 + ... + 76731.

It is an arithmetic number, because the mean of its divisors is an integer number (1633996).

Almost surely, 2^30688931 is an apocalyptic number.

30688931 is a deficient number, since it is larger than the sum of its proper divisors (8526973).

30688931 is a wasteful number, since it uses less digits than its factorization.

30688931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 30688931 is about 5539.7591102863. The cubic root of 30688931 is about 313.0837931945.

The spelling of 30688931 in words is "thirty million, six hundred eighty-eight thousand, nine hundred thirty-one".