856681677685 has 4 divisors (see below), whose sum is σ = 1028018013228. Its totient is φ = 685345342144.

The previous prime is 856681677653. The next prime is 856681677701. The reversal of 856681677685 is 586776186658.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 489689249284 + 366992428401 = 699778^2 + 605799^2 .

It is a cyclic number.

It is not a de Polignac number, because 856681677685 - 2⁵ = 856681677653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85668167764 + ... + 85668167773.

It is an arithmetic number, because the mean of its divisors is an integer number (257004503307).

Almost surely, 2^856681677685 is an apocalyptic number.

It is an amenable number.

856681677685 is a deficient number, since it is larger than the sum of its proper divisors (171336335543).

856681677685 is a wasteful number, since it uses less digits than its factorization.

856681677685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171336335542.

The product of its digits is 812851200, while the sum is 73.

The spelling of 856681677685 in words is "eight hundred fifty-six billion, six hundred eighty-one million, six hundred seventy-seven thousand, six hundred eighty-five".