31988 has 12 divisors (see below), whose sum is σ = 61152. Its totient is φ = 14520.

The previous prime is 31981. The next prime is 31991. The reversal of 31988 is 88913.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 31988.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31988.

It is not an unprimeable number, because it can be changed into a prime (31981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 320 + ... + 407.

It is an arithmetic number, because the mean of its divisors is an integer number (5096).

2³¹⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

31988 is a deficient number, since it is larger than the sum of its proper divisors (29164).

31988 is a wasteful number, since it uses less digits than its factorization.

31988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742 (or 740 counting only the distinct ones).

The product of its digits is 1728, while the sum is 29.

The square root of 31988 is about 178.8518940353. The cubic root of 31988 is about 31.7440520406.

It can be divided in two parts, 31 and 988, that multiplied together give a triangular number (30628 = T₂₄₇).

The spelling of 31988 in words is "thirty-one thousand, nine hundred eighty-eight".