311317315721 has 2 divisors, whose sum is σ = 311317315722. Its totient is φ = 311317315720.

The previous prime is 311317315693. The next prime is 311317315831. The reversal of 311317315721 is 127513713113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 185158090000 + 126159225721 = 430300^2 + 355189^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-311317315721 is a prime.

It is not a weakly prime, because it can be changed into another prime (311317315021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155658657860 + 155658657861.

It is an arithmetic number, because the mean of its divisors is an integer number (155658657861).

Almost surely, 2^311317315721 is an apocalyptic number.

It is an amenable number.

311317315721 is a deficient number, since it is larger than the sum of its proper divisors (1).

311317315721 is an equidigital number, since it uses as much as digits as its factorization.

311317315721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13230, while the sum is 35.

The spelling of 311317315721 in words is "three hundred eleven billion, three hundred seventeen million, three hundred fifteen thousand, seven hundred twenty-one".