199997998217 has 2 divisors, whose sum is σ = 199997998218. Its totient is φ = 199997998216.

The previous prime is 199997998177. The next prime is 199997998223. The reversal of 199997998217 is 712899799991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 186503923321 + 13494074896 = 431861^2 + 116164^2 .

It is an emirp because it is prime and its reverse (712899799991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199997998217 - 2⁶ = 199997998153 is a prime.

It is not a weakly prime, because it can be changed into another prime (199997998267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99998999108 + 99998999109.

It is an arithmetic number, because the mean of its divisors is an integer number (99998999109).

Almost surely, 2^199997998217 is an apocalyptic number.

It is an amenable number.

199997998217 is a deficient number, since it is larger than the sum of its proper divisors (1).

199997998217 is an equidigital number, since it uses as much as digits as its factorization.

199997998217 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 416649744, while the sum is 80.

The spelling of 199997998217 in words is "one hundred ninety-nine billion, nine hundred ninety-seven million, nine hundred ninety-eight thousand, two hundred seventeen".