31605664 has 48 divisors (see below), whose sum is σ = 66074400. Its totient is φ = 14840064.

The previous prime is 31605619. The next prime is 31605689. The reversal of 31605664 is 46650613.

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, 137902 + ... + 138130.

It is an arithmetic number, because the mean of its divisors is an integer number (1376550).

Almost surely, 2^31605664 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 31605664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33037200).

31605664 is an abundant number, since it is smaller than the sum of its proper divisors (34468736).

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

31605664 is a wasteful number, since it uses less digits than its factorization.

31605664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 485 (or 477 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 31605664 is about 5621.8914966406. The cubic root of 31605664 is about 316.1707137187.

The spelling of 31605664 in words is "thirty-one million, six hundred five thousand, six hundred sixty-four".