664881730656 has 288 divisors, whose sum is σ = 2078277556320. Its totient is φ = 185973765120.

The previous prime is 664881730651. The next prime is 664881730679. The reversal of 664881730656 is 656037188466.

664881730656 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 664881730656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664881730651) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 25507326 + ... + 25533378.

It is an arithmetic number, because the mean of its divisors is an integer number (7216241515).

Almost surely, 2^664881730656 is an apocalyptic number.

664881730656 is a gapful number since it is divisible by the number (66) 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 664881730656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1039138778160).

664881730656 is an abundant number, since it is smaller than the sum of its proper divisors (1413395825664).

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

664881730656 is a wasteful number, since it uses less digits than its factorization.

664881730656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26127 (or 26082 counting only the distinct ones).

The product of its (nonzero) digits is 34836480, while the sum is 60.

The spelling of 664881730656 in words is "six hundred sixty-four billion, eight hundred eighty-one million, seven hundred thirty thousand, six hundred fifty-six".