31991604 has 12 divisors (see below), whose sum is σ = 74647104. Its totient is φ = 10663864.

The previous prime is 31991591. The next prime is 31991621. The reversal of 31991604 is 40619913.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

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, 1332972 + ... + 1332995.

It is an arithmetic number, because the mean of its divisors is an integer number (6220592).

Almost surely, 2^31991604 is an apocalyptic number.

It is an amenable number.

31991604 is an abundant number, since it is smaller than the sum of its proper divisors (42655500).

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

31991604 is a wasteful number, since it uses less digits than its factorization.

31991604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2665974 (or 2665972 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 31991604 is about 5656.1120922415. The cubic root of 31991604 is about 317.4524416748.

The spelling of 31991604 in words is "thirty-one million, nine hundred ninety-one thousand, six hundred four".