856681673618 has 4 divisors (see below), whose sum is σ = 1285022510430. Its totient is φ = 428340836808.

The previous prime is 856681673587. The next prime is 856681673621. The reversal of 856681673618 is 816376186658.

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

It can be written as a sum of positive squares in only one way, i.e., 681478317289 + 175203356329 = 825517^2 + 418573^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214170418403 + ... + 214170418406.

Almost surely, 2^856681673618 is an apocalyptic number.

856681673618 is a deficient number, since it is larger than the sum of its proper divisors (428340836812).

856681673618 is a wasteful number, since it uses less digits than its factorization.

856681673618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428340836811.

The product of its digits is 69672960, while the sum is 65.

The spelling of 856681673618 in words is "eight hundred fifty-six billion, six hundred eighty-one million, six hundred seventy-three thousand, six hundred eighteen".