228912221 has 4 divisors (see below), whose sum is σ = 229091100. Its totient is φ = 228733344.

The previous prime is 228912179. The next prime is 228912239. The reversal of 228912221 is 122219822.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122219822 = 2 ⋅61109911.

It can be written as a sum of positive squares in 2 ways, for example, as 102799321 + 126112900 = 10139^2 + 11230^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-228912221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (228912421) 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, 87506 + ... + 90083.

It is an arithmetic number, because the mean of its divisors is an integer number (57272775).

Almost surely, 2^228912221 is an apocalyptic number.

It is an amenable number.

228912221 is a deficient number, since it is larger than the sum of its proper divisors (178879).

228912221 is a wasteful number, since it uses less digits than its factorization.

228912221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178878.

The product of its digits is 2304, while the sum is 29.

The square root of 228912221 is about 15129.8453726401. The cubic root of 228912221 is about 611.7251362642.

The spelling of 228912221 in words is "two hundred twenty-eight million, nine hundred twelve thousand, two hundred twenty-one".