31113868021 has 2 divisors, whose sum is σ = 31113868022. Its totient is φ = 31113868020.

The previous prime is 31113868013. The next prime is 31113868039. The reversal of 31113868021 is 12086831113.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30995363025 + 118504996 = 176055^2 + 10886^2 .

It is a cyclic number.

It is not a de Polignac number, because 31113868021 - 2³ = 31113868013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31113868001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15556934010 + 15556934011.

It is an arithmetic number, because the mean of its divisors is an integer number (15556934011).

Almost surely, 2^31113868021 is an apocalyptic number.

It is an amenable number.

31113868021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31113868021 is an equidigital number, since it uses as much as digits as its factorization.

31113868021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 34.

The spelling of 31113868021 in words is "thirty-one billion, one hundred thirteen million, eight hundred sixty-eight thousand, twenty-one".