664304640 has 176 divisors, whose sum is σ = 2162614560. Its totient is φ = 173998080.

The previous prime is 664304639. The next prime is 664304647. The reversal of 664304640 is 46403466.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664304647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 936606 + ... + 937314.

Almost surely, 2^664304640 is an apocalyptic number.

664304640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664304640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081307280).

664304640 is an abundant number, since it is smaller than the sum of its proper divisors (1498309920).

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

664304640 is a wasteful number, since it uses less digits than its factorization.

664304640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798 (or 780 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 33.

The square root of 664304640 is about 25774.1079380063. The cubic root of 664304640 is about 872.5475336922.

The spelling of 664304640 in words is "six hundred sixty-four million, three hundred four thousand, six hundred forty".