685199917 has 2 divisors, whose sum is σ = 685199918. Its totient is φ = 685199916.

The previous prime is 685199903. The next prime is 685199939. The reversal of 685199917 is 719991586.

685199917 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 601769961 + 83429956 = 24531^2 + 9134^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685199917 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685193917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342599958 + 342599959.

It is an arithmetic number, because the mean of its divisors is an integer number (342599959).

Almost surely, 2^685199917 is an apocalyptic number.

It is an amenable number.

685199917 is a deficient number, since it is larger than the sum of its proper divisors (1).

685199917 is an equidigital number, since it uses as much as digits as its factorization.

685199917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1224720, while the sum is 55.

The square root of 685199917 is about 26176.3235959521. The cubic root of 685199917 is about 881.6017303138.

The spelling of 685199917 in words is "six hundred eighty-five million, one hundred ninety-nine thousand, nine hundred seventeen".