31997664 has 36 divisors (see below), whose sum is σ = 90994176. Its totient is φ = 10665792.

The previous prime is 31997627. The next prime is 31997683. The reversal of 31997664 is 46679913.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 55264 + ... + 55839.

It is an arithmetic number, because the mean of its divisors is an integer number (2527616).

Almost surely, 2^31997664 is an apocalyptic number.

It is an amenable number.

31997664 is an abundant number, since it is smaller than the sum of its proper divisors (58996512).

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

31997664 is a wasteful number, since it uses less digits than its factorization.

31997664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111119 (or 111108 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 31997664 is about 5656.6477705440. The cubic root of 31997664 is about 317.4724848539.

The spelling of 31997664 in words is "thirty-one million, nine hundred ninety-seven thousand, six hundred sixty-four".