664303221 has 8 divisors (see below), whose sum is σ = 984152960. Its totient is φ = 442868796.

The previous prime is 664303207. The next prime is 664303253. The reversal of 664303221 is 122303466.

664303221 is a `hidden beast` number, since 6 + 6 + 430 + 3 + 221 = 666.

It is not a de Polignac number, because 664303221 - 2¹⁴ = 664286837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 24603823 = 664303221 / (6 + 6 + 4 + 3 + 0 + 3 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664303421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12301885 + ... + 12301938.

It is an arithmetic number, because the mean of its divisors is an integer number (123019120).

Almost surely, 2^664303221 is an apocalyptic number.

It is an amenable number.

664303221 is a deficient number, since it is larger than the sum of its proper divisors (319849739).

664303221 is a wasteful number, since it uses less digits than its factorization.

664303221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24603832 (or 24603826 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 664303221 is about 25774.0804103658. The cubic root of 664303221 is about 872.5469124181.

Adding to 664303221 its reverse (122303466), we get a palindrome (786606687).

The spelling of 664303221 in words is "six hundred sixty-four million, three hundred three thousand, two hundred twenty-one".