685667317 has 4 divisors (see below), whose sum is σ = 685732780. Its totient is φ = 685601856.

The previous prime is 685667309. The next prime is 685667321. The reversal of 685667317 is 713766586.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 562923076 + 122744241 = 23726^2 + 11079^2 .

It is a 3-Lehmer number, since φ(685667317) divides (685667317-1)³.

It is a cyclic number.

It is not a de Polignac number, because 685667317 - 2³ = 685667309 is a prime.

It is a super-3 number, since 3×685667317³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685667357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13092 + ... + 39277.

It is an arithmetic number, because the mean of its divisors is an integer number (171433195).

Almost surely, 2^685667317 is an apocalyptic number.

685667317 is the 13093-rd decagonal number.

It is an amenable number.

685667317 is a deficient number, since it is larger than the sum of its proper divisors (65463).

685667317 is a wasteful number, since it uses less digits than its factorization.

685667317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65462.

The product of its digits is 1270080, while the sum is 49.

The square root of 685667317 is about 26185.2499892592. The cubic root of 685667317 is about 881.8021423786.

The spelling of 685667317 in words is "six hundred eighty-five million, six hundred sixty-seven thousand, three hundred seventeen".