199979 has 4 divisors (see below), whose sum is σ = 215376. Its totient is φ = 184584.

The previous prime is 199967. The next prime is 199999. The reversal of 199979 is 979991.

199979 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 979991 = 97 ⋅10103.

It is a cyclic number.

It is not a de Polignac number, because 199979 - 2¹² = 195883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199909) 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, 7679 + ... + 7704.

It is an arithmetic number, because the mean of its divisors is an integer number (53844).

2¹⁹⁹⁹⁷⁹ is an apocalyptic number.

199979 is a deficient number, since it is larger than the sum of its proper divisors (15397).

199979 is a wasteful number, since it uses less digits than its factorization.

199979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15396.

The product of its digits is 45927, while the sum is 44.

The square root of 199979 is about 447.1901161698. The cubic root of 199979 is about 58.4783078802.

The spelling of 199979 in words is "one hundred ninety-nine thousand, nine hundred seventy-nine".