685820 has 24 divisors (see below), whose sum is σ = 1469664. Its totient is φ = 268736.

The previous prime is 685819. The next prime is 685849. The reversal of 685820 is 28586.

It is a happy number.

It is a nialpdrome 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 7 ways as a sum of consecutive naturals, for example, 737 + ... + 1383.

It is an arithmetic number, because the mean of its divisors is an integer number (61236).

2⁶⁸⁵⁸²⁰ is an apocalyptic number.

It is an amenable number.

685820 is an abundant number, since it is smaller than the sum of its proper divisors (783844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

685820 is a wasteful number, since it uses less digits than its factorization.

685820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709 (or 707 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 685820 is about 828.1424998151. The cubic root of 685820 is about 88.1867590155.

The spelling of 685820 in words is "six hundred eighty-five thousand, eight hundred twenty".