664306644 has 12 divisors (see below), whose sum is σ = 1550048864. Its totient is φ = 221435544.

The previous prime is 664306639. The next prime is 664306649. The reversal of 664306644 is 446603466.

It is an interprime number because it is at equal distance from previous prime (664306639) and next prime (664306649).

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664306649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27679432 + ... + 27679455.

Almost surely, 2^664306644 is an apocalyptic number.

It is an amenable number.

664306644 is an abundant number, since it is smaller than the sum of its proper divisors (885742220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664306644 is a wasteful number, since it uses less digits than its factorization.

664306644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55358894 (or 55358892 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 39.

The square root of 664306644 is about 25774.1468142012. The cubic root of 664306644 is about 872.5484110926.

The spelling of 664306644 in words is "six hundred sixty-four million, three hundred six thousand, six hundred forty-four".