685555 has 16 divisors (see below), whose sum is σ = 907200. Its totient is φ = 494208.

The previous prime is 685547. The next prime is 685591. The reversal of 685555 is 555586.

It is not a de Polignac number, because 685555 - 2³ = 685547 is a prime.

685555 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 685555.

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 15 ways as a sum of consecutive naturals, for example, 3346 + ... + 3544.

It is an arithmetic number, because the mean of its divisors is an integer number (56700).

2⁶⁸⁵⁵⁵⁵ is an apocalyptic number.

685555 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

685555 is a deficient number, since it is larger than the sum of its proper divisors (221645).

685555 is a wasteful number, since it uses less digits than its factorization.

685555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270.

The product of its digits is 30000, while the sum is 34.

The square root of 685555 is about 827.9824877375. The cubic root of 685555 is about 88.1753991340.

The spelling of 685555 in words is "six hundred eighty-five thousand, five hundred fifty-five".