312221989 has 2 divisors, whose sum is σ = 312221990. Its totient is φ = 312221988.

The previous prime is 312221969. The next prime is 312221999. The reversal of 312221989 is 989122213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 283652964 + 28569025 = 16842^2 + 5345^2 .

It is a cyclic number.

It is not a de Polignac number, because 312221989 - 2⁵ = 312221957 is a prime.

It is a super-2 number, since 2×312221989² = 194965140830232242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312221909) 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, 156110994 + 156110995.

It is an arithmetic number, because the mean of its divisors is an integer number (156110995).

Almost surely, 2^312221989 is an apocalyptic number.

It is an amenable number.

312221989 is a deficient number, since it is larger than the sum of its proper divisors (1).

312221989 is an equidigital number, since it uses as much as digits as its factorization.

312221989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 312221989 is about 17669.8044414759. The cubic root of 312221989 is about 678.4031076552.

The spelling of 312221989 in words is "three hundred twelve million, two hundred twenty-one thousand, nine hundred eighty-nine".