856580321391 has 4 divisors (see below), whose sum is σ = 1142107095192. Its totient is φ = 571053547592.

The previous prime is 856580321347. The next prime is 856580321437. The reversal of 856580321391 is 193123085658.

It is a happy number.

856580321391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 856580321391 - 2⁹ = 856580320879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856580321321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142763386896 + ... + 142763386901.

It is an arithmetic number, because the mean of its divisors is an integer number (285526773798).

Almost surely, 2^856580321391 is an apocalyptic number.

856580321391 is a deficient number, since it is larger than the sum of its proper divisors (285526773801).

856580321391 is a wasteful number, since it uses less digits than its factorization.

856580321391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285526773800.

The product of its (nonzero) digits is 1555200, while the sum is 51.

The spelling of 856580321391 in words is "eight hundred fifty-six billion, five hundred eighty million, three hundred twenty-one thousand, three hundred ninety-one".