31991982 has 16 divisors (see below), whose sum is σ = 69800832. Its totient is φ = 9694520.

The previous prime is 31991941. The next prime is 31991989. The reversal of 31991982 is 28919913.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31991989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 242298 + ... + 242429.

It is an arithmetic number, because the mean of its divisors is an integer number (4362552).

Almost surely, 2^31991982 is an apocalyptic number.

31991982 is an abundant number, since it is smaller than the sum of its proper divisors (37808850).

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

31991982 is a wasteful number, since it uses less digits than its factorization.

31991982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 484743.

The product of its digits is 34992, while the sum is 42.

The square root of 31991982 is about 5656.1455073221. The cubic root of 31991982 is about 317.4536919669.

The spelling of 31991982 in words is "thirty-one million, nine hundred ninety-one thousand, nine hundred eighty-two".