686820 has 24 divisors (see below), whose sum is σ = 1923264. Its totient is φ = 183136.

The previous prime is 686801. The next prime is 686837. The reversal of 686820 is 28686.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5664 + ... + 5783.

It is an arithmetic number, because the mean of its divisors is an integer number (80136).

2⁶⁸⁶⁸²⁰ is an apocalyptic number.

686820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

686820 is an abundant number, since it is smaller than the sum of its proper divisors (1236444).

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

686820 is a wasteful number, since it uses less digits than its factorization.

686820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11459 (or 11457 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 686820 is about 828.7460407145. The cubic root of 686820 is about 88.2296001554.

The spelling of 686820 in words is "six hundred eighty-six thousand, eight hundred twenty".