856861055 has 4 divisors (see below), whose sum is σ = 1028233272. Its totient is φ = 685488840.

The previous prime is 856861051. The next prime is 856861063. The reversal of 856861055 is 550168658.

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

It is not a de Polignac number, because 856861055 - 2² = 856861051 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 856860997 and 856861015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856861051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85686101 + ... + 85686110.

It is an arithmetic number, because the mean of its divisors is an integer number (257058318).

Almost surely, 2^856861055 is an apocalyptic number.

856861055 is a deficient number, since it is larger than the sum of its proper divisors (171372217).

856861055 is a wasteful number, since it uses less digits than its factorization.

856861055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171372216.

The product of its (nonzero) digits is 288000, while the sum is 44.

The square root of 856861055 is about 29272.1891050191. The cubic root of 856861055 is about 949.8101393436.

The spelling of 856861055 in words is "eight hundred fifty-six million, eight hundred sixty-one thousand, fifty-five".