31991532 has 24 divisors (see below), whose sum is σ = 76665456. Its totient is φ = 10375488.

The previous prime is 31991513. The next prime is 31991539. The reversal of 31991532 is 23519913.

It is a junction number, because it is equal to n+sod(n) for n = 31991493 and 31991502.

It is not an unprimeable number, because it can be changed into a prime (31991539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35583 + ... + 36470.

It is an arithmetic number, because the mean of its divisors is an integer number (3194394).

Almost surely, 2^31991532 is an apocalyptic number.

It is an amenable number.

31991532 is an abundant number, since it is smaller than the sum of its proper divisors (44673924).

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

31991532 is a wasteful number, since it uses less digits than its factorization.

31991532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72097 (or 72095 counting only the distinct ones).

The product of its digits is 7290, while the sum is 33.

The square root of 31991532 is about 5656.1057274418. The cubic root of 31991532 is about 317.4522035228.

It can be divided in two parts, 31991 and 532, that added together give a palindrome (32523).

The spelling of 31991532 in words is "thirty-one million, nine hundred ninety-one thousand, five hundred thirty-two".