66840228 has 120 divisors (see below), whose sum is σ = 215151552. Its totient is φ = 17620416.

The previous prime is 66840203. The next prime is 66840281. The reversal of 66840228 is 82204866.

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 = 66840192 and 66840201.

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 28351 + ... + 30617.

Almost surely, 2^66840228 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 66840228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107575776).

66840228 is an abundant number, since it is smaller than the sum of its proper divisors (148311324).

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

66840228 is a wasteful number, since it uses less digits than its factorization.

66840228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2303 (or 2292 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 66840228 is about 8175.5873183521. The cubic root of 66840228 is about 405.8317064794.

The spelling of 66840228 in words is "sixty-six million, eight hundred forty thousand, two hundred twenty-eight".