664603621 has 4 divisors (see below), whose sum is σ = 725022144. Its totient is φ = 604185100.

The previous prime is 664603613. The next prime is 664603631. The reversal of 664603621 is 126306466.

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 664603621 - 2³ = 664603613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664603631) 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 3 ways as a sum of consecutive naturals, for example, 30209245 + ... + 30209266.

It is an arithmetic number, because the mean of its divisors is an integer number (181255536).

Almost surely, 2^664603621 is an apocalyptic number.

It is an amenable number.

664603621 is a deficient number, since it is larger than the sum of its proper divisors (60418523).

664603621 is a wasteful number, since it uses less digits than its factorization.

664603621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60418522.

The product of its (nonzero) digits is 31104, while the sum is 34.

The square root of 664603621 is about 25779.9073117030. The cubic root of 664603621 is about 872.6784154148.

The spelling of 664603621 in words is "six hundred sixty-four million, six hundred three thousand, six hundred twenty-one".