31213856 has 12 divisors (see below), whose sum is σ = 61452342. Its totient is φ = 15606912.

The previous prime is 31213843. The next prime is 31213859. The reversal of 31213856 is 65831213.

It can be written as a sum of positive squares in only one way, i.e., 24010000 + 7203856 = 4900^2 + 2684^2 .

It is not an unprimeable number, because it can be changed into a prime (31213859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 487685 + ... + 487748.

Almost surely, 2^31213856 is an apocalyptic number.

It is an amenable number.

31213856 is a deficient number, since it is larger than the sum of its proper divisors (30238486).

31213856 is an equidigital number, since it uses as much as digits as its factorization.

31213856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 975443 (or 975435 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 31213856 is about 5586.9361907937. The cubic root of 31213856 is about 314.8587793951.

The spelling of 31213856 in words is "thirty-one million, two hundred thirteen thousand, eight hundred fifty-six".