856609 has 8 divisors (see below), whose sum is σ = 931392. Its totient is φ = 783120.

The previous prime is 856571. The next prime is 856627. The reversal of 856609 is 906658.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 856609 - 2¹³ = 848417 is a prime.

It is an Ulam number.

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 pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1452 + ... + 1954.

It is an arithmetic number, because the mean of its divisors is an integer number (116424).

2⁸⁵⁶⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

856609 is a deficient number, since it is larger than the sum of its proper divisors (74783).

856609 is a wasteful number, since it uses less digits than its factorization.

856609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 647.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 856609 is about 925.5317390560. The cubic root of 856609 is about 94.9716997882.

The spelling of 856609 in words is "eight hundred fifty-six thousand, six hundred nine".