856851 has 16 divisors (see below), whose sum is σ = 1236384. Its totient is φ = 525824.

The previous prime is 856847. The next prime is 856853. The reversal of 856851 is 158658.

It is a cyclic number.

It is not a de Polignac number, because 856851 - 2² = 856847 is a prime.

856851 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (856853) 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, 2545 + ... + 2861.

It is an arithmetic number, because the mean of its divisors is an integer number (77274).

2⁸⁵⁶⁸⁵¹ is an apocalyptic number.

856851 is a deficient number, since it is larger than the sum of its proper divisors (379533).

856851 is a wasteful number, since it uses less digits than its factorization.

856851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390.

The product of its digits is 9600, while the sum is 33.

The square root of 856851 is about 925.6624654808. The cubic root of 856851 is about 94.9806424086.

The spelling of 856851 in words is "eight hundred fifty-six thousand, eight hundred fifty-one".