199794809 has 2 divisors, whose sum is σ = 199794810. Its totient is φ = 199794808.

The previous prime is 199794779. The next prime is 199794811. The reversal of 199794809 is 908497991.

199794809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 197683600 + 2111209 = 14060^2 + 1453^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199794809 is a prime.

Together with 199794811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199794869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99897404 + 99897405.

It is an arithmetic number, because the mean of its divisors is an integer number (99897405).

Almost surely, 2^199794809 is an apocalyptic number.

It is an amenable number.

199794809 is a deficient number, since it is larger than the sum of its proper divisors (1).

199794809 is an equidigital number, since it uses as much as digits as its factorization.

199794809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1469664, while the sum is 56.

The square root of 199794809 is about 14134.8791646763. The cubic root of 199794809 is about 584.6034851674.

The spelling of 199794809 in words is "one hundred ninety-nine million, seven hundred ninety-four thousand, eight hundred nine".