664363728 has 320 divisors, whose sum is σ = 2374451200. Its totient is φ = 173560320.

The previous prime is 664363727. The next prime is 664363751. The reversal of 664363728 is 827363466.

664363728 is a `hidden beast` number, since 6 + 6 + 4 + 3 + 637 + 2 + 8 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664363727) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1780950 + ... + 1781322.

It is an arithmetic number, because the mean of its divisors is an integer number (7420160).

Almost surely, 2^664363728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664363728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1187225600).

664363728 is an abundant number, since it is smaller than the sum of its proper divisors (1710087472).

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

664363728 is a wasteful number, since it uses less digits than its factorization.

664363728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447 (or 435 counting only the distinct ones).

The product of its digits is 870912, while the sum is 45.

The square root of 664363728 is about 25775.2541791541. The cubic root of 664363728 is about 872.5734031287.

The spelling of 664363728 in words is "six hundred sixty-four million, three hundred sixty-three thousand, seven hundred twenty-eight".