688712657 has 2 divisors, whose sum is σ = 688712658. Its totient is φ = 688712656.

The previous prime is 688712623. The next prime is 688712659. The reversal of 688712657 is 756217886.

688712657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 656948161 + 31764496 = 25631^2 + 5636^2 .

It is a cyclic number.

It is not a de Polignac number, because 688712657 - 2¹⁴ = 688696273 is a prime.

Together with 688712659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (688712659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344356328 + 344356329.

It is an arithmetic number, because the mean of its divisors is an integer number (344356329).

Almost surely, 2^688712657 is an apocalyptic number.

It is an amenable number.

688712657 is a deficient number, since it is larger than the sum of its proper divisors (1).

688712657 is an equidigital number, since it uses as much as digits as its factorization.

688712657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1128960, while the sum is 50.

The square root of 688712657 is about 26243.3354777932. The cubic root of 688712657 is about 883.1057004364.

The spelling of 688712657 in words is "six hundred eighty-eight million, seven hundred twelve thousand, six hundred fifty-seven".