856643 has 4 divisors (see below), whose sum is σ = 867048. Its totient is φ = 846240.

The previous prime is 856637. The next prime is 856649. The reversal of 856643 is 346658.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (856637) and next prime (856649).

It is a cyclic number.

It is not a de Polignac number, because 856643 - 2⁴ = 856627 is a prime.

It is a Duffinian 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 3 ways as a sum of consecutive naturals, for example, 5078 + ... + 5243.

It is an arithmetic number, because the mean of its divisors is an integer number (216762).

2⁸⁵⁶⁶⁴³ is an apocalyptic number.

856643 is a gapful number since it is divisible by the number (83) formed by its first and last digit.

856643 is a deficient number, since it is larger than the sum of its proper divisors (10405).

856643 is a wasteful number, since it uses less digits than its factorization.

856643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10404.

The product of its digits is 17280, while the sum is 32.

The square root of 856643 is about 925.5501066933. The cubic root of 856643 is about 94.9729562911.

The spelling of 856643 in words is "eight hundred fifty-six thousand, six hundred forty-three".