686085859809 has 27 divisors (see below), whose sum is σ = 1152840162513. Its totient is φ = 392039123112.

The previous prime is 686085859777. The next prime is 686085859829. The reversal of 686085859809 is 908958580686.

The square root of 686085859809 is 828303.

It is a perfect power (a square), and thus also a powerful number.

686085859809 is a `hidden beast` number, since 6 + 8 + 608 + 5 + 8 + 5 + 9 + 8 + 0 + 9 = 666.

It is not a de Polignac number, because 686085859809 - 2⁵ = 686085859777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (686085859829) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 17374642 + ... + 17414084.

Almost surely, 2^686085859809 is an apocalyptic number.

686085859809 is the 828303-rd square number.

686085859809 is the 414152-nd centered octagonal number.

It is an amenable number.

686085859809 is a deficient number, since it is larger than the sum of its proper divisors (466754302704).

686085859809 is an frugal number, since it uses more digits than its factorization.

686085859809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78906 (or 39453 counting only the distinct ones).

The product of its (nonzero) digits is 298598400, while the sum is 72.

The spelling of 686085859809 in words is "six hundred eighty-six billion, eighty-five million, eight hundred fifty-nine thousand, eight hundred nine".