311720509 has 2 divisors, whose sum is σ = 311720510. Its totient is φ = 311720508.

The previous prime is 311720503. The next prime is 311720561. The reversal of 311720509 is 905027113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 205836409 + 105884100 = 14347^2 + 10290^2 .

It is a cyclic number.

It is not a de Polignac number, because 311720509 - 2⁵ = 311720477 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311720503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155860254 + 155860255.

It is an arithmetic number, because the mean of its divisors is an integer number (155860255).

Almost surely, 2^311720509 is an apocalyptic number.

It is an amenable number.

311720509 is a deficient number, since it is larger than the sum of its proper divisors (1).

311720509 is an equidigital number, since it uses as much as digits as its factorization.

311720509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 311720509 is about 17655.6084290517. The cubic root of 311720509 is about 678.0397039369.

The spelling of 311720509 in words is "three hundred eleven million, seven hundred twenty thousand, five hundred nine".