31856013 has 24 divisors (see below), whose sum is σ = 53081600. Its totient is φ = 18032544.

The previous prime is 31856009. The next prime is 31856023. The reversal of 31856013 is 31065813.

It is not a de Polignac number, because 31856013 - 2² = 31856009 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31856023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4548 + ... + 9186.

Almost surely, 2^31856013 is an apocalyptic number.

It is an amenable number.

31856013 is a deficient number, since it is larger than the sum of its proper divisors (21225587).

31856013 is a wasteful number, since it uses less digits than its factorization.

31856013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4761 (or 4758 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 31856013 is about 5644.1131278528. The cubic root of 31856013 is about 317.0033170779.

The spelling of 31856013 in words is "thirty-one million, eight hundred fifty-six thousand, thirteen".