31112021081 has 2 divisors, whose sum is σ = 31112021082. Its totient is φ = 31112021080.

The previous prime is 31112021063. The next prime is 31112021093. The reversal of 31112021081 is 18012021113.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23015620681 + 8096400400 = 151709^2 + 89980^2 .

It is a cyclic number.

It is not a de Polignac number, because 31112021081 - 2²² = 31107826777 is a prime.

It is a super-2 number, since 2×31112021081² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31112021581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15556010540 + 15556010541.

It is an arithmetic number, because the mean of its divisors is an integer number (15556010541).

Almost surely, 2^31112021081 is an apocalyptic number.

It is an amenable number.

31112021081 is a deficient number, since it is larger than the sum of its proper divisors (1).

31112021081 is an equidigital number, since it uses as much as digits as its factorization.

31112021081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 20.

Adding to 31112021081 its reverse (18012021113), we get a palindrome (49124042194).

The spelling of 31112021081 in words is "thirty-one billion, one hundred twelve million, twenty-one thousand, eighty-one".