688536631 has 2 divisors, whose sum is σ = 688536632. Its totient is φ = 688536630.

The previous prime is 688536593. The next prime is 688536637. The reversal of 688536631 is 136635886.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 688536631 - 2⁷ = 688536503 is a prime.

It is a super-2 number, since 2×688536631² = 948165384457660322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688536637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344268315 + 344268316.

It is an arithmetic number, because the mean of its divisors is an integer number (344268316).

Almost surely, 2^688536631 is an apocalyptic number.

688536631 is a deficient number, since it is larger than the sum of its proper divisors (1).

688536631 is an equidigital number, since it uses as much as digits as its factorization.

688536631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 46.

The square root of 688536631 is about 26239.9815358167. The cubic root of 688536631 is about 883.0304572475.

The spelling of 688536631 in words is "six hundred eighty-eight million, five hundred thirty-six thousand, six hundred thirty-one".