8642221 has 4 divisors (see below), whose sum is σ = 9876832. Its totient is φ = 7407612.

The previous prime is 8642197. The next prime is 8642237. The reversal of 8642221 is 1222468.

It is a happy number.

8642221 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 8642221 - 2⁵ = 8642189 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8642281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 617295 + ... + 617308.

It is an arithmetic number, because the mean of its divisors is an integer number (2469208).

Almost surely, 2^8642221 is an apocalyptic number.

It is an amenable number.

8642221 is a deficient number, since it is larger than the sum of its proper divisors (1234611).

8642221 is a wasteful number, since it uses less digits than its factorization.

8642221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1234610.

The product of its digits is 1536, while the sum is 25.

The square root of 8642221 is about 2939.7654668357. The cubic root of 8642221 is about 205.2146947642.

Adding to 8642221 its reverse (1222468), we get a palindrome (9864689).

The spelling of 8642221 in words is "eight million, six hundred forty-two thousand, two hundred twenty-one".