6644221 has 8 divisors (see below), whose sum is σ = 6761664. Its totient is φ = 6528000.

The previous prime is 6644191. The next prime is 6644227. The reversal of 6644221 is 1224466.

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

It is a cyclic number.

It is not a de Polignac number, because 6644221 - 2¹⁹ = 6119933 is a prime.

It is an Ulam number.

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 (6644227) 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, 25725 + ... + 25981.

It is an arithmetic number, because the mean of its divisors is an integer number (845208).

Almost surely, 2^6644221 is an apocalyptic number.

It is an amenable number.

6644221 is a deficient number, since it is larger than the sum of its proper divisors (117443).

6644221 is a wasteful number, since it uses less digits than its factorization.

6644221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611.

The product of its digits is 2304, while the sum is 25.

The square root of 6644221 is about 2577.6386480653. The cubic root of 6644221 is about 187.9957464708.

Adding to 6644221 its reverse (1224466), we get a palindrome (7868687).

The spelling of 6644221 in words is "six million, six hundred forty-four thousand, two hundred twenty-one".