31122431321 has 2 divisors, whose sum is σ = 31122431322. Its totient is φ = 31122431320.

The previous prime is 31122431309. The next prime is 31122431359. The reversal of 31122431321 is 12313422113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30071374921 + 1051056400 = 173411^2 + 32420^2 .

It is an emirp because it is prime and its reverse (12313422113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31122431321 - 2²⁶ = 31055322457 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 (31122631321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15561215660 + 15561215661.

It is an arithmetic number, because the mean of its divisors is an integer number (15561215661).

Almost surely, 2^31122431321 is an apocalyptic number.

It is an amenable number.

31122431321 is a deficient number, since it is larger than the sum of its proper divisors (1).

31122431321 is an equidigital number, since it uses as much as digits as its factorization.

31122431321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

Adding to 31122431321 its reverse (12313422113), we get a palindrome (43435853434).

The spelling of 31122431321 in words is "thirty-one billion, one hundred twenty-two million, four hundred thirty-one thousand, three hundred twenty-one".