31257997 has 2 divisors, whose sum is σ = 31257998. Its totient is φ = 31257996.

The previous prime is 31257991. The next prime is 31258001. The reversal of 31257997 is 79975213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23755876 + 7502121 = 4874^2 + 2739^2 .

It is an emirp because it is prime and its reverse (79975213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31257997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31257991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15628998 + 15628999.

It is an arithmetic number, because the mean of its divisors is an integer number (15628999).

Almost surely, 2^31257997 is an apocalyptic number.

It is an amenable number.

31257997 is a deficient number, since it is larger than the sum of its proper divisors (1).

31257997 is an equidigital number, since it uses as much as digits as its factorization.

31257997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 119070, while the sum is 43.

The square root of 31257997 is about 5590.8851714196. The cubic root of 31257997 is about 315.0071284185.

The spelling of 31257997 in words is "thirty-one million, two hundred fifty-seven thousand, nine hundred ninety-seven".