199813 has 2 divisors, whose sum is σ = 199814. Its totient is φ = 199812.

The previous prime is 199811. The next prime is 199819. The reversal of 199813 is 318991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 199809 + 4 = 447^2 + 2^2 .

It is a cyclic number.

It is not a de Polignac number, because 199813 - 2¹ = 199811 is a prime.

Together with 199811, it forms a pair of twin primes.

It is a nialpdrome in base 12.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199811) 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, 99906 + 99907.

It is an arithmetic number, because the mean of its divisors is an integer number (99907).

2¹⁹⁹⁸¹³ is an apocalyptic number.

It is an amenable number.

199813 is a deficient number, since it is larger than the sum of its proper divisors (1).

199813 is an equidigital number, since it uses as much as digits as its factorization.

199813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 31.

The square root of 199813 is about 447.0044742505. The cubic root of 199813 is about 58.4621227035.

The spelling of 199813 in words is "one hundred ninety-nine thousand, eight hundred thirteen".