31122110021 has 2 divisors, whose sum is σ = 31122110022. Its totient is φ = 31122110020.

The previous prime is 31122110009. The next prime is 31122110081. The reversal of 31122110021 is 12001122113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18329368996 + 12792741025 = 135386^2 + 113105^2 .

It is a cyclic number.

It is not a de Polignac number, because 31122110021 - 2²⁶ = 31055001157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31122109978 and 31122110005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31122110081) 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, 15561055010 + 15561055011.

It is an arithmetic number, because the mean of its divisors is an integer number (15561055011).

Almost surely, 2^31122110021 is an apocalyptic number.

It is an amenable number.

31122110021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31122110021 is an equidigital number, since it uses as much as digits as its factorization.

31122110021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 31122110021 its reverse (12001122113), we get a palindrome (43123232134).

The spelling of 31122110021 in words is "thirty-one billion, one hundred twenty-two million, one hundred ten thousand, twenty-one".