198966221 has 2 divisors, whose sum is σ = 198966222. Its totient is φ = 198966220.

The previous prime is 198966199. The next prime is 198966223. The reversal of 198966221 is 122669891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 168870025 + 30096196 = 12995^2 + 5486^2 .

It is an emirp because it is prime and its reverse (122669891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198966221 - 2¹⁰ = 198965197 is a prime.

Together with 198966223, 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 (198966223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99483110 + 99483111.

It is an arithmetic number, because the mean of its divisors is an integer number (99483111).

Almost surely, 2^198966221 is an apocalyptic number.

It is an amenable number.

198966221 is a deficient number, since it is larger than the sum of its proper divisors (1).

198966221 is an equidigital number, since it uses as much as digits as its factorization.

198966221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 44.

The square root of 198966221 is about 14105.5386639433. The cubic root of 198966221 is about 583.7942105429.

The spelling of 198966221 in words is "one hundred ninety-eight million, nine hundred sixty-six thousand, two hundred twenty-one".