317506661981 has 2 divisors, whose sum is σ = 317506661982. Its totient is φ = 317506661980.

The previous prime is 317506661957. The next prime is 317506662013. The reversal of 317506661981 is 189166605713.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 264946972900 + 52559689081 = 514730^2 + 229259^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-317506661981 is a prime.

It is a super-2 number, since 2×317506661981² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (317506661951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 158753330990 + 158753330991.

It is an arithmetic number, because the mean of its divisors is an integer number (158753330991).

Almost surely, 2^317506661981 is an apocalyptic number.

It is an amenable number.

317506661981 is a deficient number, since it is larger than the sum of its proper divisors (1).

317506661981 is an equidigital number, since it uses as much as digits as its factorization.

317506661981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1632960, while the sum is 53.

The spelling of 317506661981 in words is "three hundred seventeen billion, five hundred six million, six hundred sixty-one thousand, nine hundred eighty-one".