856689 has 16 divisors (see below), whose sum is σ = 1214400. Its totient is φ = 536256.

The previous prime is 856649. The next prime is 856693. The reversal of 856689 is 986658.

It is a de Polignac number, because none of the positive numbers 2^k-856689 is a prime.

856689 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 856689.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3627 + ... + 3855.

It is an arithmetic number, because the mean of its divisors is an integer number (75900).

2⁸⁵⁶⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

856689 is a deficient number, since it is larger than the sum of its proper divisors (357711).

856689 is a wasteful number, since it uses less digits than its factorization.

856689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304.

The product of its digits is 103680, while the sum is 42.

The square root of 856689 is about 925.5749564460. The cubic root of 856689 is about 94.9746562127.

The spelling of 856689 in words is "eight hundred fifty-six thousand, six hundred eighty-nine".