221828 has 6 divisors (see below), whose sum is σ = 388206. Its totient is φ = 110912.

The previous prime is 221827. The next prime is 221831. The reversal of 221828 is 828122.

It can be written as a sum of positive squares in only one way, i.e., 114244 + 107584 = 338^2 + 328^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221828.

It is not an unprimeable number, because it can be changed into a prime (221827) 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 as a sum of consecutive naturals, namely, 27725 + ... + 27732.

It is an arithmetic number, because the mean of its divisors is an integer number (64701).

2²²¹⁸²⁸ is an apocalyptic number.

It is an amenable number.

221828 is a deficient number, since it is larger than the sum of its proper divisors (166378).

221828 is a wasteful number, since it uses less digits than its factorization.

221828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55461 (or 55459 counting only the distinct ones).

The product of its digits is 512, while the sum is 23.

The square root of 221828 is about 470.9861993732. The cubic root of 221828 is about 60.5348477609.

The spelling of 221828 in words is "two hundred twenty-one thousand, eight hundred twenty-eight".