31997916 has 60 divisors (see below), whose sum is σ = 85072680. Its totient is φ = 10484640.

The previous prime is 31997909. The next prime is 31997963. The reversal of 31997916 is 61979913.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 18955 + ... + 20573.

It is an arithmetic number, because the mean of its divisors is an integer number (1417878).

Almost surely, 2^31997916 is an apocalyptic number.

31997916 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31997916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42536340).

31997916 is an abundant number, since it is smaller than the sum of its proper divisors (53074764).

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

31997916 is a wasteful number, since it uses less digits than its factorization.

31997916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1696 (or 1685 counting only the distinct ones).

The product of its digits is 91854, while the sum is 45.

The square root of 31997916 is about 5656.6700451768. The cubic root of 31997916 is about 317.4733182778.

The spelling of 31997916 in words is "thirty-one million, nine hundred ninety-seven thousand, nine hundred sixteen".