199985729 has 2 divisors, whose sum is σ = 199985730. Its totient is φ = 199985728.

The previous prime is 199985707. The next prime is 199985749. The reversal of 199985729 is 927589991.

199985729 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172318129 + 27667600 = 13127^2 + 5260^2 .

It is a cyclic number.

It is not a de Polignac number, because 199985729 - 2²⁴ = 183208513 is a prime.

It is a super-2 number, since 2×199985729² = 79988583607322882, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (199985749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99992864 + 99992865.

It is an arithmetic number, because the mean of its divisors is an integer number (99992865).

Almost surely, 2^199985729 is an apocalyptic number.

It is an amenable number.

199985729 is a deficient number, since it is larger than the sum of its proper divisors (1).

199985729 is an equidigital number, since it uses as much as digits as its factorization.

199985729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3674160, while the sum is 59.

The square root of 199985729 is about 14141.6310586863. The cubic root of 199985729 is about 584.7896377593.

The spelling of 199985729 in words is "one hundred ninety-nine million, nine hundred eighty-five thousand, seven hundred twenty-nine".