66810228 has 12 divisors (see below), whose sum is σ = 155890560. Its totient is φ = 22270072.

The previous prime is 66810223. The next prime is 66810241. The reversal of 66810228 is 82201866.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66810223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2783748 + ... + 2783771.

It is an arithmetic number, because the mean of its divisors is an integer number (12990880).

Almost surely, 2^66810228 is an apocalyptic number.

It is an amenable number.

66810228 is an abundant number, since it is smaller than the sum of its proper divisors (89080332).

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

66810228 is a wasteful number, since it uses less digits than its factorization.

66810228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5567526 (or 5567524 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 66810228 is about 8173.7523818623. The cubic root of 66810228 is about 405.7709807083.

The spelling of 66810228 in words is "sixty-six million, eight hundred ten thousand, two hundred twenty-eight".