685009 has 16 divisors (see below), whose sum is σ = 806400. Its totient is φ = 576576.

The previous prime is 685001. The next prime is 685019. The reversal of 685009 is 900586.

It is not a de Polignac number, because 685009 - 2³ = 685001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685001) 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 15 ways as a sum of consecutive naturals, for example, 8632 + ... + 8710.

It is an arithmetic number, because the mean of its divisors is an integer number (50400).

2⁶⁸⁵⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

685009 is a deficient number, since it is larger than the sum of its proper divisors (121391).

685009 is a wasteful number, since it uses less digits than its factorization.

685009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 685009 is about 827.6527049433. The cubic root of 685009 is about 88.1519842586.

The spelling of 685009 in words is "six hundred eighty-five thousand, nine".