199421813 has 2 divisors, whose sum is σ = 199421814. Its totient is φ = 199421812.

The previous prime is 199421801. The next prime is 199421819. The reversal of 199421813 is 318124991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 107702884 + 91718929 = 10378^2 + 9577^2 .

It is a cyclic number.

It is not a de Polignac number, because 199421813 - 2¹⁴ = 199405429 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199421819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99710906 + 99710907.

It is an arithmetic number, because the mean of its divisors is an integer number (99710907).

Almost surely, 2^199421813 is an apocalyptic number.

It is an amenable number.

199421813 is a deficient number, since it is larger than the sum of its proper divisors (1).

199421813 is an equidigital number, since it uses as much as digits as its factorization.

199421813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 38.

The square root of 199421813 is about 14121.6788307906. The cubic root of 199421813 is about 584.2394606986.

The spelling of 199421813 in words is "one hundred ninety-nine million, four hundred twenty-one thousand, eight hundred thirteen".