856791 has 16 divisors (see below), whose sum is σ = 1367520. Its totient is φ = 527040.

The previous prime is 856789. The next prime is 856799. The reversal of 856791 is 197658.

856791 is a `hidden beast` number, since 8 + 567 + 91 = 666.

It is not a de Polignac number, because 856791 - 2¹ = 856789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856799) 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 15 ways as a sum of consecutive naturals, for example, 870 + ... + 1571.

It is an arithmetic number, because the mean of its divisors is an integer number (85470).

2⁸⁵⁶⁷⁹¹ is an apocalyptic number.

856791 is a deficient number, since it is larger than the sum of its proper divisors (510729).

856791 is a wasteful number, since it uses less digits than its factorization.

856791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2463 (or 2457 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 856791 is about 925.6300556918. The cubic root of 856791 is about 94.9784253870.

The spelling of 856791 in words is "eight hundred fifty-six thousand, seven hundred ninety-one".