66630728 has 8 divisors (see below), whose sum is σ = 124932630. Its totient is φ = 33315360.

The previous prime is 66630709. The next prime is 66630743. The reversal of 66630728 is 82703666.

66630728 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 49308484 + 17322244 = 7022^2 + 4162^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 66630691 and 66630700.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4164413 + ... + 4164428.

Almost surely, 2^66630728 is an apocalyptic number.

It is an amenable number.

66630728 is a deficient number, since it is larger than the sum of its proper divisors (58301902).

66630728 is a wasteful number, since it uses less digits than its factorization.

66630728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8328847 (or 8328843 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 38.

The square root of 66630728 is about 8162.7647277133. The cubic root of 66630728 is about 405.4072578648.

The spelling of 66630728 in words is "sixty-six million, six hundred thirty thousand, seven hundred twenty-eight".