685845 has 12 divisors (see below), whose sum is σ = 1188876. Its totient is φ = 365760.

The previous prime is 685819. The next prime is 685849. The reversal of 685845 is 548586.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 400689 + 285156 = 633^2 + 534^2 .

It is not a de Polignac number, because 685845 - 2⁶ = 685781 is a prime.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685849) 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 11 ways as a sum of consecutive naturals, for example, 7576 + ... + 7665.

It is an arithmetic number, because the mean of its divisors is an integer number (99073).

2⁶⁸⁵⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

685845 is a deficient number, since it is larger than the sum of its proper divisors (503031).

685845 is a wasteful number, since it uses less digits than its factorization.

685845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15252 (or 15249 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The square root of 685845 is about 828.1575936982. The cubic root of 685845 is about 88.1878305514.

It can be divided in two parts, 6858 and 45, that added together give a triangular number (6903 = T₁₁₇).

The spelling of 685845 in words is "six hundred eighty-five thousand, eight hundred forty-five".