313121021989 has 2 divisors, whose sum is σ = 313121021990. Its totient is φ = 313121021988.

The previous prime is 313121021987. The next prime is 313121022077. The reversal of 313121021989 is 989120121313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 285601529889 + 27519492100 = 534417^2 + 165890^2 .

It is an emirp because it is prime and its reverse (989120121313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 313121021989 - 2¹ = 313121021987 is a prime.

It is a super-2 number, since 2×313121021989² (a number of 24 digits) contains 22 as substring.

Together with 313121021987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (313121021987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 156560510994 + 156560510995.

It is an arithmetic number, because the mean of its divisors is an integer number (156560510995).

Almost surely, 2^313121021989 is an apocalyptic number.

It is an amenable number.

313121021989 is a deficient number, since it is larger than the sum of its proper divisors (1).

313121021989 is an equidigital number, since it uses as much as digits as its factorization.

313121021989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 40.

The spelling of 313121021989 in words is "three hundred thirteen billion, one hundred twenty-one million, twenty-one thousand, nine hundred eighty-nine".