685737971731 has 2 divisors, whose sum is σ = 685737971732. Its totient is φ = 685737971730.

The previous prime is 685737971707. The next prime is 685737971749. The reversal of 685737971731 is 137179737586.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 685737971731 - 2³¹ = 683590488083 is a prime.

It is a super-2 number, since 2×685737971731² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (685737971531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342868985865 + 342868985866.

It is an arithmetic number, because the mean of its divisors is an integer number (342868985866).

Almost surely, 2^685737971731 is an apocalyptic number.

685737971731 is a deficient number, since it is larger than the sum of its proper divisors (1).

685737971731 is an equidigital number, since it uses as much as digits as its factorization.

685737971731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46675440, while the sum is 64.

The spelling of 685737971731 in words is "six hundred eighty-five billion, seven hundred thirty-seven million, nine hundred seventy-one thousand, seven hundred thirty-one".