31890920 has 16 divisors (see below), whose sum is σ = 71754660. Its totient is φ = 12756352.

The previous prime is 31890919. The next prime is 31890959. The reversal of 31890920 is 2909813.

It can be written as a sum of positive squares in 2 ways, for example, as 29181604 + 2709316 = 5402^2 + 1646^2 .

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, 398597 + ... + 398676.

Almost surely, 2^31890920 is an apocalyptic number.

It is an amenable number.

31890920 is an abundant number, since it is smaller than the sum of its proper divisors (39863740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31890920 is a wasteful number, since it uses less digits than its factorization.

31890920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797284 (or 797280 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 31890920 is about 5647.2046182160. The cubic root of 31890920 is about 317.1190628393.

The spelling of 31890920 in words is "thirty-one million, eight hundred ninety thousand, nine hundred twenty".