221228 has 12 divisors (see below), whose sum is σ = 442512. Its totient is φ = 94800.

The previous prime is 221227. The next prime is 221233. The reversal of 221228 is 822122.

221228 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

221228 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (221227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3923 + ... + 3978.

It is an arithmetic number, because the mean of its divisors is an integer number (36876).

2²²¹²²⁸ is an apocalyptic number.

221228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

221228 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

221228 is a wasteful number, since it uses less digits than its factorization.

221228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7912 (or 7910 counting only the distinct ones).

The product of its digits is 128, while the sum is 17.

The square root of 221228 is about 470.3488067381. The cubic root of 221228 is about 60.4802202944.

The spelling of 221228 in words is "two hundred twenty-one thousand, two hundred twenty-eight".