664564736 has 88 divisors (see below), whose sum is σ = 1485630720. Its totient is φ = 294502400.

The previous prime is 664564723. The next prime is 664564739. The reversal of 664564736 is 637465466.

It is a tau number, because it is divible by the number of its divisors (88).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664564739) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 461105 + ... + 462543.

Almost surely, 2^664564736 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 664564736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (742815360).

664564736 is an abundant number, since it is smaller than the sum of its proper divisors (821065984).

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

664564736 is a wasteful number, since it uses less digits than its factorization.

664564736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1511 (or 1493 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 47.

The square root of 664564736 is about 25779.1531280607. The cubic root of 664564736 is about 872.6613953641.

The spelling of 664564736 in words is "six hundred sixty-four million, five hundred sixty-four thousand, seven hundred thirty-six".