198221 has 2 divisors, whose sum is σ = 198222. Its totient is φ = 198220.

The previous prime is 198197. The next prime is 198223. The reversal of 198221 is 122891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198025 + 196 = 445^2 + 14^2 .

It is an emirp because it is prime and its reverse (122891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198221 - 2¹⁴ = 181837 is a prime.

It is a Sophie Germain prime.

Together with 198223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99110 + 99111.

It is an arithmetic number, because the mean of its divisors is an integer number (99111).

2¹⁹⁸²²¹ is an apocalyptic number.

It is an amenable number.

198221 is a deficient number, since it is larger than the sum of its proper divisors (1).

198221 is an equidigital number, since it uses as much as digits as its factorization.

198221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 23.

The square root of 198221 is about 445.2201702529. The cubic root of 198221 is about 58.3064438427.

The spelling of 198221 in words is "one hundred ninety-eight thousand, two hundred twenty-one".