856879 has 4 divisors (see below), whose sum is σ = 864576. Its totient is φ = 849184.

The previous prime is 856853. The next prime is 856897. The reversal of 856879 is 978658.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 978658 = 2 ⋅489329.

It is a cyclic number.

It is not a de Polignac number, because 856879 - 2⁵ = 856847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3679 + ... + 3904.

It is an arithmetic number, because the mean of its divisors is an integer number (216144).

2⁸⁵⁶⁸⁷⁹ is an apocalyptic number.

856879 is a deficient number, since it is larger than the sum of its proper divisors (7697).

856879 is a wasteful number, since it uses less digits than its factorization.

856879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7696.

The product of its digits is 120960, while the sum is 43.

The square root of 856879 is about 925.6775896607. The cubic root of 856879 is about 94.9816769833.

The spelling of 856879 in words is "eight hundred fifty-six thousand, eight hundred seventy-nine".