31313020997 has 2 divisors, whose sum is σ = 31313020998. Its totient is φ = 31313020996.

The previous prime is 31313020891. The next prime is 31313021057. The reversal of 31313020997 is 79902031313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31127897761 + 185123236 = 176431^2 + 13606^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31313020997 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31313020997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31313050997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15656510498 + 15656510499.

It is an arithmetic number, because the mean of its divisors is an integer number (15656510499).

Almost surely, 2^31313020997 is an apocalyptic number.

It is an amenable number.

31313020997 is a deficient number, since it is larger than the sum of its proper divisors (1).

31313020997 is an equidigital number, since it uses as much as digits as its factorization.

31313020997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30618, while the sum is 38.

The spelling of 31313020997 in words is "thirty-one billion, three hundred thirteen million, twenty thousand, nine hundred ninety-seven".