31991120 has 60 divisors (see below), whose sum is σ = 86533524. Its totient is φ = 10967040.

The previous prime is 31991119. The next prime is 31991143. The reversal of 31991120 is 2119913.

It can be written as a sum of positive squares in 2 ways, for example, as 11669056 + 20322064 = 3416^2 + 4508^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 31991120.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 161 + ... + 8000.

Almost surely, 2^31991120 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31991120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43266762).

31991120 is an abundant number, since it is smaller than the sum of its proper divisors (54542404).

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

31991120 is a wasteful number, since it uses less digits than its factorization.

31991120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8188 (or 8175 counting only the distinct ones).

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 31991120 is about 5656.0693065061. The cubic root of 31991120 is about 317.4508407573.

The spelling of 31991120 in words is "thirty-one million, nine hundred ninety-one thousand, one hundred twenty".