199999813 has 4 divisors (see below), whose sum is σ = 215384428. Its totient is φ = 184615200.

The previous prime is 199999777. The next prime is 199999819. The reversal of 199999813 is 318999991.

It is the 5774-th star number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14577124 + 185422689 = 3818^2 + 13617^2 .

It is a cyclic number.

It is not a de Polignac number, because 199999813 - 2¹⁷ = 199868741 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 (199999819) 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, 7692288 + ... + 7692313.

It is an arithmetic number, because the mean of its divisors is an integer number (53846107).

Almost surely, 2^199999813 is an apocalyptic number.

199999813 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

199999813 is a deficient number, since it is larger than the sum of its proper divisors (15384615).

199999813 is a wasteful number, since it uses less digits than its factorization.

199999813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15384614.

The product of its digits is 1417176, while the sum is 58.

The square root of 199999813 is about 14142.1290122810. The cubic root of 199999813 is about 584.8033653787.

The spelling of 199999813 in words is "one hundred ninety-nine million, nine hundred ninety-nine thousand, eight hundred thirteen".