199985209 has 2 divisors, whose sum is σ = 199985210. Its totient is φ = 199985208.

The previous prime is 199985197. The next prime is 199985221. The reversal of 199985209 is 902589991.

It is a balanced prime because it is at equal distance from previous prime (199985197) and next prime (199985221).

It can be written as a sum of positive squares in only one way, i.e., 195021225 + 4963984 = 13965^2 + 2228^2 .

It is an emirp because it is prime and its reverse (902589991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199985209 - 2¹³ = 199977017 is a prime.

It is not a weakly prime, because it can be changed into another prime (199985809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99992604 + 99992605.

It is an arithmetic number, because the mean of its divisors is an integer number (99992605).

Almost surely, 2^199985209 is an apocalyptic number.

It is an amenable number.

199985209 is a deficient number, since it is larger than the sum of its proper divisors (1).

199985209 is an equidigital number, since it uses as much as digits as its factorization.

199985209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 524880, while the sum is 52.

The square root of 199985209 is about 14141.6126732420. The cubic root of 199985209 is about 584.7891309050.

The spelling of 199985209 in words is "one hundred ninety-nine million, nine hundred eighty-five thousand, two hundred nine".