198351221 has 2 divisors, whose sum is σ = 198351222. Its totient is φ = 198351220.

The previous prime is 198351187. The next prime is 198351227. The reversal of 198351221 is 122153891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135466321 + 62884900 = 11639^2 + 7930^2 .

It is a cyclic number.

It is not a de Polignac number, because 198351221 - 2²⁶ = 131242357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198351227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99175610 + 99175611.

It is an arithmetic number, because the mean of its divisors is an integer number (99175611).

Almost surely, 2^198351221 is an apocalyptic number.

It is an amenable number.

198351221 is a deficient number, since it is larger than the sum of its proper divisors (1).

198351221 is an equidigital number, since it uses as much as digits as its factorization.

198351221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 32.

The square root of 198351221 is about 14083.7218447398. The cubic root of 198351221 is about 583.1920915909.

The spelling of 198351221 in words is "one hundred ninety-eight million, three hundred fifty-one thousand, two hundred twenty-one".