199999 has 2 divisors, whose sum is σ = 200000. Its totient is φ = 199998.

The previous prime is 199967. The next prime is 200003. The reversal of 199999 is 999991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199999 - 2⁵ = 199967 is a prime.

It is a fibodiv number, since the Fibonacci-like sequence with seeds 1 and 99999 contains 199999 itself.

199999 is a modest number, since divided by 999 gives 199 as remainder.

199999 is a lucky number.

It is a plaindrome in base 5 and base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99999 + 100000.

It is an arithmetic number, because the mean of its divisors is an integer number (100000).

2¹⁹⁹⁹⁹⁹ is an apocalyptic number.

199999 is a deficient number, since it is larger than the sum of its proper divisors (1).

199999 is an equidigital number, since it uses as much as digits as its factorization.

199999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 59049, while the sum is 46.

The square root of 199999 is about 447.2124774646. The cubic root of 199999 is about 58.4802572968.

It can be divided in two parts, 19 and 9999, that multiplied together give a palindrome (189981).

The spelling of 199999 in words is "one hundred ninety-nine thousand, nine hundred ninety-nine".