31000023121 has 2 divisors, whose sum is σ = 31000023122. Its totient is φ = 31000023120.

The previous prime is 31000023113. The next prime is 31000023143. The reversal of 31000023121 is 12132000013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30029077521 + 970945600 = 173289^2 + 31160^2 .

It is a cyclic number.

It is not a de Polignac number, because 31000023121 - 2³ = 31000023113 is a prime.

It is a super-2 number, since 2×31000023121² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31000023101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15500011560 + 15500011561.

It is an arithmetic number, because the mean of its divisors is an integer number (15500011561).

Almost surely, 2^31000023121 is an apocalyptic number.

It is an amenable number.

31000023121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31000023121 is an equidigital number, since it uses as much as digits as its factorization.

31000023121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 13.

Adding to 31000023121 its reverse (12132000013), we get a palindrome (43132023134).

The spelling of 31000023121 in words is "thirty-one billion, twenty-three thousand, one hundred twenty-one".