199987517 has 2 divisors, whose sum is σ = 199987518. Its totient is φ = 199987516.

The previous prime is 199987427. The next prime is 199987523. The reversal of 199987517 is 715789991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 170328601 + 29658916 = 13051^2 + 5446^2 .

It is a cyclic number.

It is not a de Polignac number, because 199987517 - 2⁸ = 199987261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199987537) 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, 99993758 + 99993759.

It is an arithmetic number, because the mean of its divisors is an integer number (99993759).

Almost surely, 2^199987517 is an apocalyptic number.

It is an amenable number.

199987517 is a deficient number, since it is larger than the sum of its proper divisors (1).

199987517 is an equidigital number, since it uses as much as digits as its factorization.

199987517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1428840, while the sum is 56.

The square root of 199987517 is about 14141.6942761467. The cubic root of 199987517 is about 584.7913805516.

The spelling of 199987517 in words is "one hundred ninety-nine million, nine hundred eighty-seven thousand, five hundred seventeen".