856009 has 8 divisors (see below), whose sum is σ = 1067328. Its totient is φ = 666960.

The previous prime is 855997. The next prime is 856021. The reversal of 856009 is 900658.

It is an interprime number because it is at equal distance from previous prime (855997) and next prime (856021).

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

It is not a de Polignac number, because 856009 - 2¹³ = 847817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856099) 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 7 ways as a sum of consecutive naturals, for example, 5482 + ... + 5635.

It is an arithmetic number, because the mean of its divisors is an integer number (133416).

2⁸⁵⁶⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

856009 is a deficient number, since it is larger than the sum of its proper divisors (211319).

856009 is a wasteful number, since it uses less digits than its factorization.

856009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11135.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 856009 is about 925.2075442840. The cubic root of 856009 is about 94.9495207351.

The spelling of 856009 in words is "eight hundred fifty-six thousand, nine".