31311307861 has 2 divisors, whose sum is σ = 31311307862. Its totient is φ = 31311307860.

The previous prime is 31311307843. The next prime is 31311307871. The reversal of 31311307861 is 16870311313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17409483025 + 13901824836 = 131945^2 + 117906^2 .

It is a cyclic number.

It is not a de Polignac number, because 31311307861 - 2⁷ = 31311307733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31311307871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15655653930 + 15655653931.

It is an arithmetic number, because the mean of its divisors is an integer number (15655653931).

Almost surely, 2^31311307861 is an apocalyptic number.

It is an amenable number.

31311307861 is a deficient number, since it is larger than the sum of its proper divisors (1).

31311307861 is an equidigital number, since it uses as much as digits as its factorization.

31311307861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 34.

The spelling of 31311307861 in words is "thirty-one billion, three hundred eleven million, three hundred seven thousand, eight hundred sixty-one".