199811 has 2 divisors, whose sum is σ = 199812. Its totient is φ = 199810.

The previous prime is 199807. The next prime is 199813. The reversal of 199811 is 118991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 199811 - 2² = 199807 is a prime.

Together with 199813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (199813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99905 + 99906.

It is an arithmetic number, because the mean of its divisors is an integer number (99906).

2¹⁹⁹⁸¹¹ is an apocalyptic number.

199811 is a deficient number, since it is larger than the sum of its proper divisors (1).

199811 is an equidigital number, since it uses as much as digits as its factorization.

199811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 29.

The square root of 199811 is about 447.0022371309. The cubic root of 199811 is about 58.4619276467.

The spelling of 199811 in words is "one hundred ninety-nine thousand, eight hundred eleven".