856647 has 24 divisors (see below), whose sum is σ = 1432080. Its totient is φ = 487680.

The previous prime is 856637. The next prime is 856649. The reversal of 856647 is 746658.

It is a happy number.

856647 is a `hidden beast` number, since 8 + 5 + 6 + 647 = 666.

It is not a de Polignac number, because 856647 - 2⁷ = 856519 is a prime.

856647 is a lucky number.

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 23 ways as a sum of consecutive naturals, for example, 1429 + ... + 1937.

It is an arithmetic number, because the mean of its divisors is an integer number (59670).

2⁸⁵⁶⁶⁴⁷ is an apocalyptic number.

856647 is a deficient number, since it is larger than the sum of its proper divisors (575433).

856647 is a wasteful number, since it uses less digits than its factorization.

856647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 543 (or 540 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 856647 is about 925.5522675679. The cubic root of 856647 is about 94.9731041128.

The spelling of 856647 in words is "eight hundred fifty-six thousand, six hundred forty-seven".