311951993 has 2 divisors, whose sum is σ = 311951994. Its totient is φ = 311951992.

The previous prime is 311951963. The next prime is 311952007. The reversal of 311951993 is 399159113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195916009 + 116035984 = 13997^2 + 10772^2 .

It is a cyclic number.

It is not a de Polignac number, because 311951993 - 2⁶ = 311951929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 311951993.

It is not a weakly prime, because it can be changed into another prime (311951923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155975996 + 155975997.

It is an arithmetic number, because the mean of its divisors is an integer number (155975997).

Almost surely, 2^311951993 is an apocalyptic number.

It is an amenable number.

311951993 is a deficient number, since it is larger than the sum of its proper divisors (1).

311951993 is an equidigital number, since it uses as much as digits as its factorization.

311951993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32805, while the sum is 41.

The square root of 311951993 is about 17662.1627497880. The cubic root of 311951993 is about 678.2075000903.

The spelling of 311951993 in words is "three hundred eleven million, nine hundred fifty-one thousand, nine hundred ninety-three".