688717717 has 2 divisors, whose sum is σ = 688717718. Its totient is φ = 688717716.

The previous prime is 688717703. The next prime is 688717739. The reversal of 688717717 is 717717886.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 375816996 + 312900721 = 19386^2 + 17689^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688717717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688717417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344358858 + 344358859.

It is an arithmetic number, because the mean of its divisors is an integer number (344358859).

Almost surely, 2^688717717 is an apocalyptic number.

It is an amenable number.

688717717 is a deficient number, since it is larger than the sum of its proper divisors (1).

688717717 is an equidigital number, since it uses as much as digits as its factorization.

688717717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 921984, while the sum is 52.

The square root of 688717717 is about 26243.4318830446. The cubic root of 688717717 is about 883.1078631690.

The spelling of 688717717 in words is "six hundred eighty-eight million, seven hundred seventeen thousand, seven hundred seventeen".