31997405257 has 2 divisors, whose sum is σ = 31997405258. Its totient is φ = 31997405256.

The previous prime is 31997405233. The next prime is 31997405329. The reversal of 31997405257 is 75250479913.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21227324416 + 10770080841 = 145696^2 + 103779^2 .

It is a cyclic number.

It is not a de Polignac number, because 31997405257 - 2¹¹ = 31997403209 is a prime.

It is not a weakly prime, because it can be changed into another prime (31997405227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15998702628 + 15998702629.

It is an arithmetic number, because the mean of its divisors is an integer number (15998702629).

Almost surely, 2^31997405257 is an apocalyptic number.

It is an amenable number.

31997405257 is a deficient number, since it is larger than the sum of its proper divisors (1).

31997405257 is an equidigital number, since it uses as much as digits as its factorization.

31997405257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2381400, while the sum is 52.

The spelling of 31997405257 in words is "thirty-one billion, nine hundred ninety-seven million, four hundred five thousand, two hundred fifty-seven".