31221111112913 has 2 divisors, whose sum is σ = 31221111112914. Its totient is φ = 31221111112912.

The previous prime is 31221111112847. The next prime is 31221111112937. The reversal of 31221111112913 is 31921111112213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23530095713089 + 7691015399824 = 4850783^2 + 2773268^2 .

It is a cyclic number.

It is not a de Polignac number, because 31221111112913 - 2³² = 31216816145617 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (31221111712913) 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, 15610555556456 + 15610555556457.

It is an arithmetic number, because the mean of its divisors is an integer number (15610555556457).

Almost surely, 2^{31221111112913} is an apocalyptic number.

It is an amenable number.

31221111112913 is a deficient number, since it is larger than the sum of its proper divisors (1).

31221111112913 is an equidigital number, since it uses as much as digits as its factorization.

31221111112913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 29.

The spelling of 31221111112913 in words is "thirty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred twelve thousand, nine hundred thirteen".