856221 has 8 divisors (see below), whose sum is σ = 1191360. Its totient is φ = 545952.

The previous prime is 856213. The next prime is 856237. The reversal of 856221 is 122658.

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

It is not a de Polignac number, because 856221 - 2³ = 856213 is a prime.

It is a super-2 number, since 2×856221² = 1466228801682, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 856191 and 856200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6136 + ... + 6273.

It is an arithmetic number, because the mean of its divisors is an integer number (148920).

2⁸⁵⁶²²¹ is an apocalyptic number.

It is an amenable number.

856221 is a deficient number, since it is larger than the sum of its proper divisors (335139).

856221 is a wasteful number, since it uses less digits than its factorization.

856221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12435.

The product of its digits is 960, while the sum is 24.

The square root of 856221 is about 925.3221060798. The cubic root of 856221 is about 94.9573585176.

Adding to 856221 its reverse (122658), we get a palindrome (978879).

The spelling of 856221 in words is "eight hundred fifty-six thousand, two hundred twenty-one".