199999879 has 4 divisors (see below), whose sum is σ = 206451520. Its totient is φ = 193548240.

The previous prime is 199999853. The next prime is 199999889. The reversal of 199999879 is 978999991.

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 199999879 - 2¹⁵ = 199967111 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 (199999819) 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, 3225774 + ... + 3225835.

It is an arithmetic number, because the mean of its divisors is an integer number (51612880).

Almost surely, 2^199999879 is an apocalyptic number.

199999879 is a deficient number, since it is larger than the sum of its proper divisors (6451641).

199999879 is an equidigital number, since it uses as much as digits as its factorization.

199999879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6451640.

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

The square root of 199999879 is about 14142.1313457343. The cubic root of 199999879 is about 584.8034297072.

The spelling of 199999879 in words is "one hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred seventy-nine".