685885 has 4 divisors (see below), whose sum is σ = 823068. Its totient is φ = 548704.

The previous prime is 685859. The next prime is 685907. The reversal of 685885 is 588586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 588586 = 2 ⋅294293.

It can be written as a sum of positive squares in 2 ways, for example, as 329476 + 356409 = 574^2 + 597^2 .

It is a cyclic number.

It is not a de Polignac number, because 685885 - 2¹⁵ = 653117 is a prime.

It is a Duffinian number.

685885 is a lucky number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68584 + ... + 68593.

It is an arithmetic number, because the mean of its divisors is an integer number (205767).

2⁶⁸⁵⁸⁸⁵ is an apocalyptic number.

It is an amenable number.

685885 is a deficient number, since it is larger than the sum of its proper divisors (137183).

685885 is a wasteful number, since it uses less digits than its factorization.

685885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137182.

The product of its digits is 76800, while the sum is 40.

The square root of 685885 is about 828.1817433390. The cubic root of 685885 is about 88.1895449546.

The spelling of 685885 in words is "six hundred eighty-five thousand, eight hundred eighty-five".