686666685 has 16 divisors (see below), whose sum is σ = 1099050624. Its totient is φ = 366094272.

The previous prime is 686666671. The next prime is 686666711. The reversal of 686666685 is 586666686.

It is not a de Polignac number, because 686666685 - 2⁶ = 686666621 is a prime.

It is a super-2 number, since 2×686666685² = 943022272577778450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49864 + ... + 62126.

It is an arithmetic number, because the mean of its divisors is an integer number (68690664).

Almost surely, 2^686666685 is an apocalyptic number.

It is an amenable number.

686666685 is a deficient number, since it is larger than the sum of its proper divisors (412383939).

686666685 is a wasteful number, since it uses less digits than its factorization.

686666685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16004.

The product of its digits is 14929920, while the sum is 57.

The square root of 686666685 is about 26204.3256925264. The cubic root of 686666685 is about 882.2303466629.

Subtracting from 686666685 its reverse (586666686), we obtain a palindrome (99999999).

The spelling of 686666685 in words is "six hundred eighty-six million, six hundred sixty-six thousand, six hundred eighty-five".