228810221 has 2 divisors, whose sum is σ = 228810222. Its totient is φ = 228810220.

The previous prime is 228810137. The next prime is 228810223. The reversal of 228810221 is 122018822.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 209844196 + 18966025 = 14486^2 + 4355^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-228810221 is a prime.

Together with 228810223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (228810223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 114405110 + 114405111.

It is an arithmetic number, because the mean of its divisors is an integer number (114405111).

Almost surely, 2^228810221 is an apocalyptic number.

It is an amenable number.

228810221 is a deficient number, since it is larger than the sum of its proper divisors (1).

228810221 is an equidigital number, since it uses as much as digits as its factorization.

228810221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 228810221 is about 15126.4741760927. The cubic root of 228810221 is about 611.6342641190.

The spelling of 228810221 in words is "two hundred twenty-eight million, eight hundred ten thousand, two hundred twenty-one".