664814656 has 63 divisors (see below), whose sum is σ = 1455041413. Its totient is φ = 301157120.

The previous prime is 664814641. The next prime is 664814663. The reversal of 664814656 is 656418466.

The square root of 664814656 is 25784.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 629006400 + 35808256 = 25080^2 + 5984^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2268846 + ... + 2269138.

Almost surely, 2^664814656 is an apocalyptic number.

664814656 is the 25784-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664814656

664814656 is an abundant number, since it is smaller than the sum of its proper divisors (790226757).

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

664814656 is an equidigital number, since it uses as much as digits as its factorization.

664814656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620 (or 306 counting only the distinct ones).

The product of its digits is 829440, while the sum is 46.

The cubic root of 664814656 is about 872.7707743257.

The spelling of 664814656 in words is "six hundred sixty-four million, eight hundred fourteen thousand, six hundred fifty-six".