8356821 has 16 divisors (see below), whose sum is σ = 12325440. Its totient is φ = 4993920.

The previous prime is 8356781. The next prime is 8356837. The reversal of 8356821 is 1286538.

It is a happy number.

8356821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 8356821 - 2¹³ = 8348629 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8356861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 675 + ... + 4143.

It is an arithmetic number, because the mean of its divisors is an integer number (770340).

Almost surely, 2^8356821 is an apocalyptic number.

It is an amenable number.

8356821 is a deficient number, since it is larger than the sum of its proper divisors (3968619).

8356821 is a wasteful number, since it uses less digits than its factorization.

8356821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3556.

The product of its digits is 11520, while the sum is 33.

The square root of 8356821 is about 2890.8166666186. The cubic root of 8356821 is about 202.9303634898.

The spelling of 8356821 in words is "eight million, three hundred fifty-six thousand, eight hundred twenty-one".