228221 has 4 divisors (see below), whose sum is σ = 260832. Its totient is φ = 195612.

The previous prime is 228211. The next prime is 228223. The reversal of 228221 is 122822.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-228221 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 228221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16295 + ... + 16308.

It is an arithmetic number, because the mean of its divisors is an integer number (65208).

2²²⁸²²¹ is an apocalyptic number.

It is an amenable number.

228221 is a deficient number, since it is larger than the sum of its proper divisors (32611).

228221 is an equidigital number, since it uses as much as digits as its factorization.

228221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32610.

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

The square root of 228221 is about 477.7248161861. The cubic root of 228221 is about 61.1108795828.

The spelling of 228221 in words is "two hundred twenty-eight thousand, two hundred twenty-one".