31608040861 has 2 divisors, whose sum is σ = 31608040862. Its totient is φ = 31608040860.

The previous prime is 31608040787. The next prime is 31608040873. The reversal of 31608040861 is 16804080613.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19020547225 + 12587493636 = 137915^2 + 112194^2 .

It is a cyclic number.

It is not a de Polignac number, because 31608040861 - 2²⁵ = 31574486429 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31608040861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31608020861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15804020430 + 15804020431.

It is an arithmetic number, because the mean of its divisors is an integer number (15804020431).

Almost surely, 2^31608040861 is an apocalyptic number.

It is an amenable number.

31608040861 is a deficient number, since it is larger than the sum of its proper divisors (1).

31608040861 is an equidigital number, since it uses as much as digits as its factorization.

31608040861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 37.

The spelling of 31608040861 in words is "thirty-one billion, six hundred eight million, forty thousand, eight hundred sixty-one".