6644521 has 8 divisors (see below), whose sum is σ = 7277760. Its totient is φ = 6028752.

The previous prime is 6644503. The next prime is 6644527. The reversal of 6644521 is 1254466.

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 6644521 - 2²¹ = 4547369 is a prime.

It is a Duffinian number.

6644521 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 6644521.

It is not an unprimeable number, because it can be changed into a prime (6644527) 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 7 ways as a sum of consecutive naturals, for example, 3565 + ... + 5098.

It is an arithmetic number, because the mean of its divisors is an integer number (909720).

Almost surely, 2^6644521 is an apocalyptic number.

It is an amenable number.

6644521 is a deficient number, since it is larger than the sum of its proper divisors (633239).

6644521 is a wasteful number, since it uses less digits than its factorization.

6644521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8735.

The product of its digits is 5760, while the sum is 28.

The square root of 6644521 is about 2577.6968402044. The cubic root of 6644521 is about 187.9985758908.

Adding to 6644521 its reverse (1254466), we get a palindrome (7898987).

It can be divided in two parts, 66445 and 21, that added together give a palindrome (66466).

The spelling of 6644521 in words is "six million, six hundred forty-four thousand, five hundred twenty-one".