199397813 has 2 divisors, whose sum is σ = 199397814. Its totient is φ = 199397812.

The previous prime is 199397717. The next prime is 199397831. The reversal of 199397813 is 318793991.

It is a happy number.

Together with next prime (199397831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 189145009 + 10252804 = 13753^2 + 3202^2 .

It is a cyclic number.

It is not a de Polignac number, because 199397813 - 2²⁰ = 198349237 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199397873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99698906 + 99698907.

It is an arithmetic number, because the mean of its divisors is an integer number (99698907).

Almost surely, 2^199397813 is an apocalyptic number.

It is an amenable number.

199397813 is a deficient number, since it is larger than the sum of its proper divisors (1).

199397813 is an equidigital number, since it uses as much as digits as its factorization.

199397813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 50.

The square root of 199397813 is about 14120.8290478994. The cubic root of 199397813 is about 584.2160224241.

It can be divided in two parts, 1993978 and 13, that added together give a palindrome (1993991).

The spelling of 199397813 in words is "one hundred ninety-nine million, three hundred ninety-seven thousand, eight hundred thirteen".