199841209 has 2 divisors, whose sum is σ = 199841210. Its totient is φ = 199841208.

The previous prime is 199841207. The next prime is 199841237. The reversal of 199841209 is 902148991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184199184 + 15642025 = 13572^2 + 3955^2 .

It is a cyclic number.

It is not a de Polignac number, because 199841209 - 2¹ = 199841207 is a prime.

Together with 199841207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (199841203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99920604 + 99920605.

It is an arithmetic number, because the mean of its divisors is an integer number (99920605).

Almost surely, 2^199841209 is an apocalyptic number.

It is an amenable number.

199841209 is a deficient number, since it is larger than the sum of its proper divisors (1).

199841209 is an equidigital number, since it uses as much as digits as its factorization.

199841209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 43.

The square root of 199841209 is about 14136.5203993062. The cubic root of 199841209 is about 584.6487374310.

The spelling of 199841209 in words is "one hundred ninety-nine million, eight hundred forty-one thousand, two hundred nine".