199992809 has 2 divisors, whose sum is σ = 199992810. Its totient is φ = 199992808.

The previous prime is 199992791. The next prime is 199992817. The reversal of 199992809 is 908299991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180983209 + 19009600 = 13453^2 + 4360^2 .

It is a cyclic number.

It is not a de Polignac number, because 199992809 - 2²⁰ = 198944233 is a prime.

It is a super-3 number, since 3×199992809³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (199992829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99996404 + 99996405.

It is an arithmetic number, because the mean of its divisors is an integer number (99996405).

Almost surely, 2^199992809 is an apocalyptic number.

It is an amenable number.

199992809 is a deficient number, since it is larger than the sum of its proper divisors (1).

199992809 is an equidigital number, since it uses as much as digits as its factorization.

199992809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 944784, while the sum is 56.

The square root of 199992809 is about 14141.8813812024. The cubic root of 199992809 is about 584.7965386881.

The spelling of 199992809 in words is "one hundred ninety-nine million, nine hundred ninety-two thousand, eight hundred nine".