31686545731 has 2 divisors, whose sum is σ = 31686545732. Its totient is φ = 31686545730.

The previous prime is 31686545711. The next prime is 31686545741. The reversal of 31686545731 is 13754568613.

It is a strong prime.

It is an emirp because it is prime and its reverse (13754568613) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31686545731 - 2²³ = 31678157123 is a prime.

It is a super-2 number, since 2×31686545731² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31686545711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15843272865 + 15843272866.

It is an arithmetic number, because the mean of its divisors is an integer number (15843272866).

Almost surely, 2^31686545731 is an apocalyptic number.

31686545731 is a deficient number, since it is larger than the sum of its proper divisors (1).

31686545731 is an equidigital number, since it uses as much as digits as its factorization.

31686545731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1814400, while the sum is 49.

The spelling of 31686545731 in words is "thirty-one billion, six hundred eighty-six million, five hundred forty-five thousand, seven hundred thirty-one".