199999823 has 4 divisors (see below), whose sum is σ = 200329920. Its totient is φ = 199669728.

The previous prime is 199999819. The next prime is 199999831. The reversal of 199999823 is 328999991.

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 199999823 - 2² = 199999819 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 (199999853) 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, 164138 + ... + 165351.

It is an arithmetic number, because the mean of its divisors is an integer number (50082480).

Almost surely, 2^199999823 is an apocalyptic number.

199999823 is a deficient number, since it is larger than the sum of its proper divisors (330097).

199999823 is an equidigital number, since it uses as much as digits as its factorization.

199999823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330096.

The product of its digits is 2834352, while the sum is 59.

The square root of 199999823 is about 14142.1293658346. The cubic root of 199999823 is about 584.8033751255.

It can be divided in two parts, 1999998 and 23, that multiplied together give a palindrome (45999954).

The spelling of 199999823 in words is "one hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred twenty-three".