31315913 has 2 divisors, whose sum is σ = 31315914. Its totient is φ = 31315912.

The previous prime is 31315901. The next prime is 31315927. The reversal of 31315913 is 31951313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22771984 + 8543929 = 4772^2 + 2923^2 .

It is a cyclic number.

It is not a de Polignac number, because 31315913 - 2⁴ = 31315897 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31315993) 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, 15657956 + 15657957.

It is an arithmetic number, because the mean of its divisors is an integer number (15657957).

Almost surely, 2^31315913 is an apocalyptic number.

It is an amenable number.

31315913 is a deficient number, since it is larger than the sum of its proper divisors (1).

31315913 is an equidigital number, since it uses as much as digits as its factorization.

31315913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1215, while the sum is 26.

The square root of 31315913 is about 5596.0622762796. The cubic root of 31315913 is about 315.2015607610.

The spelling of 31315913 in words is "thirty-one million, three hundred fifteen thousand, nine hundred thirteen".