66205728 has 192 divisors, whose sum is σ = 210672000. Its totient is φ = 20155392.

The previous prime is 66205723. The next prime is 66205781. The reversal of 66205728 is 82750266.

66205728 is a `hidden beast` number, since 6 + 620 + 5 + 7 + 28 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 66205692 and 66205701.

It is not an unprimeable number, because it can be changed into a prime (66205721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 607338 + ... + 607446.

It is an arithmetic number, because the mean of its divisors is an integer number (1097250).

Almost surely, 2^66205728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66205728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105336000).

66205728 is an abundant number, since it is smaller than the sum of its proper divisors (144466272).

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

66205728 is a wasteful number, since it uses less digits than its factorization.

66205728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184 (or 170 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 66205728 is about 8136.6902362078. The cubic root of 66205728 is about 404.5434636147.

The spelling of 66205728 in words is "sixty-six million, two hundred five thousand, seven hundred twenty-eight".