31904 has 12 divisors (see below), whose sum is σ = 62874. Its totient is φ = 15936.

The previous prime is 31891. The next prime is 31907. The reversal of 31904 is 40913.

It can be written as a sum of positive squares in only one way, i.e., 21904 + 10000 = 148^2 + 100^2 .

It is not an unprimeable number, because it can be changed into a prime (31907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 467 + ... + 530.

2³¹⁹⁰⁴ is an apocalyptic number.

It is an amenable number.

31904 is a deficient number, since it is larger than the sum of its proper divisors (30970).

31904 is an equidigital number, since it uses as much as digits as its factorization.

31904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1007 (or 999 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 31904 is about 178.6169084941. The cubic root of 31904 is about 31.7162412173.

Subtracting 31904 from its reverse (40913), we obtain a palindrome (9009).

The spelling of 31904 in words is "thirty-one thousand, nine hundred four".