31809664 has 32 divisors (see below), whose sum is σ = 63767340. Its totient is φ = 15805440.

The previous prime is 31809653. The next prime is 31809719. The reversal of 31809664 is 46690813.

It can be written as a sum of positive squares in 2 ways, for example, as 31809600 + 64 = 5640^2 + 8^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22482 + ... + 23854.

Almost surely, 2^31809664 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 31809664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31883670).

31809664 is an abundant number, since it is smaller than the sum of its proper divisors (31957676).

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

31809664 is a wasteful number, since it uses less digits than its factorization.

31809664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1568 (or 1556 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 31809664 is about 5640.0056737560. The cubic root of 31809664 is about 316.8495008185.

It can be divided in two parts, 318096 and 64, that multiplied together give a square (20358144 = 4512²).

The spelling of 31809664 in words is "thirty-one million, eight hundred nine thousand, six hundred sixty-four".