8639221 has 4 divisors (see below), whose sum is σ = 8743392. Its totient is φ = 8535052.

The previous prime is 8639219. The next prime is 8639227. The reversal of 8639221 is 1229368.

8639221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8639221 - 2¹ = 8639219 is a prime.

It is a super-2 number, since 2×8639221² = 149272278973682, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8639227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51961 + ... + 52126.

It is an arithmetic number, because the mean of its divisors is an integer number (2185848).

Almost surely, 2^8639221 is an apocalyptic number.

It is an amenable number.

8639221 is a deficient number, since it is larger than the sum of its proper divisors (104171).

8639221 is a wasteful number, since it uses less digits than its factorization.

8639221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104170.

The product of its digits is 5184, while the sum is 31.

The square root of 8639221 is about 2939.2551777619. The cubic root of 8639221 is about 205.1909464193.

The spelling of 8639221 in words is "eight million, six hundred thirty-nine thousand, two hundred twenty-one".