31685661791 has 12 divisors (see below), whose sum is σ = 36862601328. Its totient is φ = 27156360672.

The previous prime is 31685661757. The next prime is 31685661823. The reversal of 31685661791 is 19716658613.

It is not a de Polignac number, because 31685661791 - 2²² = 31681467487 is a prime.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31685621791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 557315 + ... + 611531.

It is an arithmetic number, because the mean of its divisors is an integer number (3071883444).

Almost surely, 2^31685661791 is an apocalyptic number.

31685661791 is a deficient number, since it is larger than the sum of its proper divisors (5176939537).

31685661791 is a wasteful number, since it uses less digits than its factorization.

31685661791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66158 (or 66151 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 53.

The spelling of 31685661791 in words is "thirty-one billion, six hundred eighty-five million, six hundred sixty-one thousand, seven hundred ninety-one".