31609664 has 42 divisors (see below), whose sum is σ = 66671190. Its totient is φ = 14866432.

The previous prime is 31609661. The next prime is 31609679. The reversal of 31609664 is 46690613.

It can be written as a sum of positive squares in 3 ways, for example, as 7795264 + 23814400 = 2792^2 + 4880^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31609661) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17642 + ... + 19350.

Almost surely, 2^31609664 is an apocalyptic number.

31609664 is a gapful number since it is divisible by the number (34) 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 31609664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33335595).

31609664 is an abundant number, since it is smaller than the sum of its proper divisors (35061526).

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

31609664 is a wasteful number, since it uses less digits than its factorization.

31609664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1755 (or 1728 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 31609664 is about 5622.2472375377. The cubic root of 31609664 is about 316.1840513018.

The spelling of 31609664 in words is "thirty-one million, six hundred nine thousand, six hundred sixty-four".