6644421 has 12 divisors (see below), whose sum is σ = 10968672. Its totient is φ = 3796776.

The previous prime is 6644413. The next prime is 6644431. The reversal of 6644421 is 1244466.

It is not a de Polignac number, because 6644421 - 2³ = 6644413 is a prime.

It is a Curzon number.

6644421 is a lucky 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 (6644431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52671 + ... + 52796.

It is an arithmetic number, because the mean of its divisors is an integer number (914056).

Almost surely, 2^6644421 is an apocalyptic number.

It is an amenable number.

6644421 is a deficient number, since it is larger than the sum of its proper divisors (4324251).

6644421 is a wasteful number, since it uses less digits than its factorization.

6644421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105480 (or 105477 counting only the distinct ones).

The product of its digits is 4608, while the sum is 27.

The square root of 6644421 is about 2577.6774429707. The cubic root of 6644421 is about 187.9976327603.

Adding to 6644421 its reverse (1244466), we get a palindrome (7888887).

The spelling of 6644421 in words is "six million, six hundred forty-four thousand, four hundred twenty-one".