199969999 has 4 divisors (see below), whose sum is σ = 200004336. Its totient is φ = 199935664.

The previous prime is 199969967. The next prime is 199970011. The reversal of 199969999 is 999969991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199969999 - 2⁵ = 199969967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199969919) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6019 + ... + 20884.

It is an arithmetic number, because the mean of its divisors is an integer number (50001084).

Almost surely, 2^199969999 is an apocalyptic number.

199969999 is a deficient number, since it is larger than the sum of its proper divisors (34337).

199969999 is an equidigital number, since it uses as much as digits as its factorization.

199969999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34336.

The product of its digits is 28697814, while the sum is 70.

The square root of 199969999 is about 14141.0748884234. The cubic root of 199969999 is about 584.7743050283.

The spelling of 199969999 in words is "one hundred ninety-nine million, nine hundred sixty-nine thousand, nine hundred ninety-nine".