198951209 has 2 divisors, whose sum is σ = 198951210. Its totient is φ = 198951208.

The previous prime is 198951169. The next prime is 198951217. The reversal of 198951209 is 902159891.

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., 158055184 + 40896025 = 12572^2 + 6395^2 .

It is a cyclic number.

It is not a de Polignac number, because 198951209 - 2²⁰ = 197902633 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 198951209.

It is not a weakly prime, because it can be changed into another prime (198950209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99475604 + 99475605.

It is an arithmetic number, because the mean of its divisors is an integer number (99475605).

Almost surely, 2^198951209 is an apocalyptic number.

It is an amenable number.

198951209 is a deficient number, since it is larger than the sum of its proper divisors (1).

198951209 is an equidigital number, since it uses as much as digits as its factorization.

198951209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 58320, while the sum is 44.

The square root of 198951209 is about 14105.0065225082. The cubic root of 198951209 is about 583.7795277506.

The spelling of 198951209 in words is "one hundred ninety-eight million, nine hundred fifty-one thousand, two hundred nine".