31981120 has 56 divisors (see below), whose sum is σ = 76809600. Its totient is φ = 12682752.

The previous prime is 31981087. The next prime is 31981133. The reversal of 31981120 is 2118913.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44121 + ... + 44839.

It is an arithmetic number, because the mean of its divisors is an integer number (1371600).

Almost surely, 2^31981120 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 31981120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38404800).

31981120 is an abundant number, since it is smaller than the sum of its proper divisors (44828480).

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

31981120 is a wasteful number, since it uses less digits than its factorization.

31981120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875 (or 865 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 31981120 is about 5655.1852312723. The cubic root of 31981120 is about 317.4177603355.

The spelling of 31981120 in words is "thirty-one million, nine hundred eighty-one thousand, one hundred twenty".