685657 has 8 divisors (see below), whose sum is σ = 800000. Its totient is φ = 587412.

The previous prime is 685649. The next prime is 685669. The reversal of 685657 is 756586.

It is not a de Polignac number, because 685657 - 2³ = 685649 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (685637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 657 + ... + 1342.

It is an arithmetic number, because the mean of its divisors is an integer number (100000).

2⁶⁸⁵⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

685657 is a deficient number, since it is larger than the sum of its proper divisors (114343).

685657 is an equidigital number, since it uses as much as digits as its factorization.

685657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2020 (or 2006 counting only the distinct ones).

The product of its digits is 50400, while the sum is 37.

The square root of 685657 is about 828.0440809522. The cubic root of 685657 is about 88.1797719632.

The spelling of 685657 in words is "six hundred eighty-five thousand, six hundred fifty-seven".