31971557 has 2 divisors, whose sum is σ = 31971558. Its totient is φ = 31971556.

The previous prime is 31971551. The next prime is 31971581. The reversal of 31971557 is 75517913.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29311396 + 2660161 = 5414^2 + 1631^2 .

It is a cyclic number.

It is not a de Polignac number, because 31971557 - 2¹² = 31967461 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31971557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31971551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15985778 + 15985779.

It is an arithmetic number, because the mean of its divisors is an integer number (15985779).

Almost surely, 2^31971557 is an apocalyptic number.

It is an amenable number.

31971557 is a deficient number, since it is larger than the sum of its proper divisors (1).

31971557 is an equidigital number, since it uses as much as digits as its factorization.

31971557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33075, while the sum is 38.

The square root of 31971557 is about 5654.3396608269. The cubic root of 31971557 is about 317.3861190771.

The spelling of 31971557 in words is "thirty-one million, nine hundred seventy-one thousand, five hundred fifty-seven".