686808820 has 24 divisors (see below), whose sum is σ = 1462059144. Its totient is φ = 270959616.

The previous prime is 686808739. The next prime is 686808833. The reversal of 686808820 is 28808686.

It can be written as a sum of positive squares in 4 ways, for example, as 96707556 + 590101264 = 9834^2 + 24292^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 233749 + ... + 236668.

It is an arithmetic number, because the mean of its divisors is an integer number (60919131).

Almost surely, 2^686808820 is an apocalyptic number.

It is an amenable number.

686808820 is an abundant number, since it is smaller than the sum of its proper divisors (775250324).

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

686808820 is a wasteful number, since it uses less digits than its factorization.

686808820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 470499 (or 470497 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 46.

The square root of 686808820 is about 26207.0376044298. The cubic root of 686808820 is about 882.2912142143.

The spelling of 686808820 in words is "six hundred eighty-six million, eight hundred eight thousand, eight hundred twenty".