311213081 has 2 divisors, whose sum is σ = 311213082. Its totient is φ = 311213080.

The previous prime is 311213053. The next prime is 311213107. The reversal of 311213081 is 180312113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 308353600 + 2859481 = 17560^2 + 1691^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-311213081 is a prime.

It is a super-2 number, since 2×311213081² = 193707163571025122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (311233081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155606540 + 155606541.

It is an arithmetic number, because the mean of its divisors is an integer number (155606541).

Almost surely, 2^311213081 is an apocalyptic number.

It is an amenable number.

311213081 is a deficient number, since it is larger than the sum of its proper divisors (1).

311213081 is an equidigital number, since it uses as much as digits as its factorization.

311213081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 311213081 is about 17641.2324115976. The cubic root of 311213081 is about 677.6715929973.

Adding to 311213081 its reverse (180312113), we get a palindrome (491525194).

The spelling of 311213081 in words is "three hundred eleven million, two hundred thirteen thousand, eighty-one".