66280728 has 32 divisors (see below), whose sum is σ = 171048960. Its totient is φ = 21380640.

The previous prime is 66280717. The next prime is 66280751. The reversal of 66280728 is 82708266.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43800 + ... + 45287.

It is an arithmetic number, because the mean of its divisors is an integer number (5345280).

Almost surely, 2^66280728 is an apocalyptic number.

It is an amenable number.

66280728 is an abundant number, since it is smaller than the sum of its proper divisors (104768232).

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

66280728 is a wasteful number, since it uses less digits than its factorization.

66280728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89127 (or 89123 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 66280728 is about 8141.2976852588. The cubic root of 66280728 is about 404.6961659608.

The spelling of 66280728 in words is "sixty-six million, two hundred eighty thousand, seven hundred twenty-eight".