666280728 has 96 divisors (see below), whose sum is σ = 1981521360. Its totient is φ = 209018880.

The previous prime is 666280723. The next prime is 666280753. The reversal of 666280728 is 827082666.

It is a happy number.

666280728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666280723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22968 + ... + 43128.

Almost surely, 2^666280728 is an apocalyptic number.

666280728 is a gapful number since it is divisible by the number (68) 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 666280728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (990760680).

666280728 is an abundant number, since it is smaller than the sum of its proper divisors (1315240632).

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

666280728 is a wasteful number, since it uses less digits than its factorization.

666280728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20199 (or 20183 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The square root of 666280728 is about 25812.4142226178. The cubic root of 666280728 is about 873.4118579563.

The spelling of 666280728 in words is "six hundred sixty-six million, two hundred eighty thousand, seven hundred twenty-eight".