66021228 has 108 divisors (see below), whose sum is σ = 209139840. Its totient is φ = 17406144.

The previous prime is 66021187. The next prime is 66021239. The reversal of 66021228 is 82212066.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 21493 + ... + 24371.

It is an arithmetic number, because the mean of its divisors is an integer number (1936480).

Almost surely, 2^66021228 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 66021228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104569920).

66021228 is an abundant number, since it is smaller than the sum of its proper divisors (143118612).

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

66021228 is a wasteful number, since it uses less digits than its factorization.

66021228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2916 (or 2904 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 66021228 is about 8125.3447926842. The cubic root of 66021228 is about 404.1673244094.

The spelling of 66021228 in words is "sixty-six million, twenty-one thousand, two hundred twenty-eight".