311256989 has 2 divisors, whose sum is σ = 311256990. Its totient is φ = 311256988.

The previous prime is 311256973. The next prime is 311256991. The reversal of 311256989 is 989652113.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 300432889 + 10824100 = 17333^2 + 3290^2 .

It is an emirp because it is prime and its reverse (989652113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 311256989 - 2⁴ = 311256973 is a prime.

It is a super-2 number, since 2×311256989² = 193761826402692242, which contains 22 as substring.

Together with 311256991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311258989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155628494 + 155628495.

It is an arithmetic number, because the mean of its divisors is an integer number (155628495).

Almost surely, 2^311256989 is an apocalyptic number.

It is an amenable number.

311256989 is a deficient number, since it is larger than the sum of its proper divisors (1).

311256989 is an equidigital number, since it uses as much as digits as its factorization.

311256989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 44.

The square root of 311256989 is about 17642.4768385848. The cubic root of 311256989 is about 677.7034616289.

The spelling of 311256989 in words is "three hundred eleven million, two hundred fifty-six thousand, nine hundred eighty-nine".