685585 has 4 divisors (see below), whose sum is σ = 822708. Its totient is φ = 548464.

The previous prime is 685547. The next prime is 685591. The reversal of 685585 is 585586.

It is a happy number.

It is a Cunningham number, because it is equal to 828²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 585586 = 2 ⋅292793.

It can be written as a sum of positive squares in 2 ways, for example, as 246016 + 439569 = 496^2 + 663^2 .

It is a cyclic number.

It is not a de Polignac number, because 685585 - 2⁹ = 685073 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68554 + ... + 68563.

It is an arithmetic number, because the mean of its divisors is an integer number (205677).

2⁶⁸⁵⁵⁸⁵ is an apocalyptic number.

It is an amenable number.

685585 is a deficient number, since it is larger than the sum of its proper divisors (137123).

685585 is a wasteful number, since it uses less digits than its factorization.

685585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137122.

The product of its digits is 48000, while the sum is 37.

The square root of 685585 is about 828.0006038645. Note that the first 3 decimals coincide. The cubic root of 685585 is about 88.1766853053.

Subtracting from 685585 its reverse (585586), we obtain a palindrome (99999).

The spelling of 685585 in words is "six hundred eighty-five thousand, five hundred eighty-five".