311685917 has 2 divisors, whose sum is σ = 311685918. Its totient is φ = 311685916.

The previous prime is 311685911. The next prime is 311685947. The reversal of 311685917 is 719586113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 311663716 + 22201 = 17654^2 + 149^2 .

It is a cyclic number.

It is not a de Polignac number, because 311685917 - 2⁴ = 311685901 is a prime.

It is a super-2 number, since 2×311685917² = 194296221712261778, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311685911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155842958 + 155842959.

It is an arithmetic number, because the mean of its divisors is an integer number (155842959).

Almost surely, 2^311685917 is an apocalyptic number.

It is an amenable number.

311685917 is a deficient number, since it is larger than the sum of its proper divisors (1).

311685917 is an equidigital number, since it uses as much as digits as its factorization.

311685917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 41.

The square root of 311685917 is about 17654.6287698156. The cubic root of 311685917 is about 678.0146220484.

It can be divided in two parts, 3 and 11685917, that multiplied together give a triangular number (35057751 = T₈₃₇₃).

The spelling of 311685917 in words is "three hundred eleven million, six hundred eighty-five thousand, nine hundred seventeen".