199789999 has 4 divisors (see below), whose sum is σ = 199845360. Its totient is φ = 199734640.

The previous prime is 199789991. The next prime is 199790023. The reversal of 199789999 is 999987991.

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 199789999 - 2³ = 199789991 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 (199789991) 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 in 3 ways as a sum of consecutive naturals, for example, 21859 + ... + 29620.

It is an arithmetic number, because the mean of its divisors is an integer number (49961340).

Almost surely, 2^199789999 is an apocalyptic number.

199789999 is a deficient number, since it is larger than the sum of its proper divisors (55361).

199789999 is an equidigital number, since it uses as much as digits as its factorization.

199789999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55360.

The product of its digits is 29760696, while the sum is 70.

The square root of 199789999 is about 14134.7090171676. The cubic root of 199789999 is about 584.5987937453.

The spelling of 199789999 in words is "one hundred ninety-nine million, seven hundred eighty-nine thousand, nine hundred ninety-nine".