13231711981 has 2 divisors, whose sum is σ = 13231711982. Its totient is φ = 13231711980.

The previous prime is 13231711957. The next prime is 13231711991. The reversal of 13231711981 is 18911713231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7090482025 + 6141229956 = 84205^2 + 78366^2 .

It is a cyclic number.

It is not a de Polignac number, because 13231711981 - 2²⁷ = 13097494253 is a prime.

It is a super-2 number, since 2×13231711981² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 13231711981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13231711931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6615855990 + 6615855991.

It is an arithmetic number, because the mean of its divisors is an integer number (6615855991).

Almost surely, 2^13231711981 is an apocalyptic number.

It is an amenable number.

13231711981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13231711981 is an equidigital number, since it uses as much as digits as its factorization.

13231711981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 37.

The spelling of 13231711981 in words is "thirteen billion, two hundred thirty-one million, seven hundred eleven thousand, nine hundred eighty-one".