31312420121 has 2 divisors, whose sum is σ = 31312420122. Its totient is φ = 31312420120.

The previous prime is 31312420091. The next prime is 31312420123. The reversal of 31312420121 is 12102421313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25253977225 + 6058442896 = 158915^2 + 77836^2 .

It is a cyclic number.

It is not a de Polignac number, because 31312420121 - 2⁶ = 31312420057 is a prime.

Together with 31312420123, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31312420093 and 31312420102.

It is not a weakly prime, because it can be changed into another prime (31312420123) 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, 15656210060 + 15656210061.

It is an arithmetic number, because the mean of its divisors is an integer number (15656210061).

Almost surely, 2^31312420121 is an apocalyptic number.

It is an amenable number.

31312420121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31312420121 is an equidigital number, since it uses as much as digits as its factorization.

31312420121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 31312420121 its reverse (12102421313), we get a palindrome (43414841434).

The spelling of 31312420121 in words is "thirty-one billion, three hundred twelve million, four hundred twenty thousand, one hundred twenty-one".