686388638705 has 32 divisors (see below), whose sum is σ = 1039281159168. Its totient is φ = 422723448000.

The previous prime is 686388638657. The next prime is 686388638729. The reversal of 686388638705 is 507836883686.

It is not a de Polignac number, because 686388638705 - 2²⁴ = 686371861489 is a prime.

It is a super-2 number, since 2×686388638705² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10707971 + ... + 10771880.

It is an arithmetic number, because the mean of its divisors is an integer number (32477536224).

Almost surely, 2^686388638705 is an apocalyptic number.

It is an amenable number.

686388638705 is a deficient number, since it is larger than the sum of its proper divisors (352892520463).

686388638705 is a wasteful number, since it uses less digits than its factorization.

686388638705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21479957.

The product of its (nonzero) digits is 278691840, while the sum is 68.

The spelling of 686388638705 in words is "six hundred eighty-six billion, three hundred eighty-eight million, six hundred thirty-eight thousand, seven hundred five".