31155515515013 has 2 divisors, whose sum is σ = 31155515515014. Its totient is φ = 31155515515012.

The previous prime is 31155515515009. The next prime is 31155515515109. The reversal of 31155515515013 is 31051551555113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27190311511489 + 3965204003524 = 5214433^2 + 1991282^2 .

It is a cyclic number.

It is not a de Polignac number, because 31155515515013 - 2² = 31155515515009 is a prime.

It is a super-2 number, since 2×31155515515013² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31155515515613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15577757757506 + 15577757757507.

It is an arithmetic number, because the mean of its divisors is an integer number (15577757757507).

Almost surely, 2^{31155515515013} is an apocalyptic number.

It is an amenable number.

31155515515013 is a deficient number, since it is larger than the sum of its proper divisors (1).

31155515515013 is an equidigital number, since it uses as much as digits as its factorization.

31155515515013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 140625, while the sum is 41.

The spelling of 31155515515013 in words is "thirty-one trillion, one hundred fifty-five billion, five hundred fifteen million, five hundred fifteen thousand, thirteen".