685715717 has 2 divisors, whose sum is σ = 685715718. Its totient is φ = 685715716.

The previous prime is 685715699. The next prime is 685715729. The reversal of 685715717 is 717517586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 518427361 + 167288356 = 22769^2 + 12934^2 .

It is a cyclic number.

It is not a de Polignac number, because 685715717 - 2¹⁶ = 685650181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685715777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342857858 + 342857859.

It is an arithmetic number, because the mean of its divisors is an integer number (342857859).

Almost surely, 2^685715717 is an apocalyptic number.

It is an amenable number.

685715717 is a deficient number, since it is larger than the sum of its proper divisors (1).

685715717 is an equidigital number, since it uses as much as digits as its factorization.

685715717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 411600, while the sum is 47.

The square root of 685715717 is about 26186.1741573679. The cubic root of 685715717 is about 881.8228901564.

The spelling of 685715717 in words is "six hundred eighty-five million, seven hundred fifteen thousand, seven hundred seventeen".