6642221 has 4 divisors (see below), whose sum is σ = 6654912. Its totient is φ = 6629532.

The previous prime is 6642211. The next prime is 6642281. The reversal of 6642221 is 1222466.

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 6642221 - 2¹⁰ = 6641197 is a prime.

It is a Duffinian number.

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 (6642211) 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, 5525 + ... + 6618.

It is an arithmetic number, because the mean of its divisors is an integer number (1663728).

Almost surely, 2^6642221 is an apocalyptic number.

It is an amenable number.

6642221 is a deficient number, since it is larger than the sum of its proper divisors (12691).

6642221 is a wasteful number, since it uses less digits than its factorization.

6642221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12690.

The product of its digits is 1152, while the sum is 23.

The square root of 6642221 is about 2577.2506668929. The cubic root of 6642221 is about 187.9768814940.

Adding to 6642221 its reverse (1222466), we get a palindrome (7864687).

The spelling of 6642221 in words is "six million, six hundred forty-two thousand, two hundred twenty-one".