199989509 has 2 divisors, whose sum is σ = 199989510. Its totient is φ = 199989508.

The previous prime is 199989473. The next prime is 199989529. The reversal of 199989509 is 905989991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 155700484 + 44289025 = 12478^2 + 6655^2 .

It is a cyclic number.

It is not a de Polignac number, because 199989509 - 2¹⁶ = 199923973 is a prime.

It is a super-2 number, since 2×199989509² = 79991607420122162, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199989529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99994754 + 99994755.

It is an arithmetic number, because the mean of its divisors is an integer number (99994755).

Almost surely, 2^199989509 is an apocalyptic number.

It is an amenable number.

199989509 is a deficient number, since it is larger than the sum of its proper divisors (1).

199989509 is an equidigital number, since it uses as much as digits as its factorization.

199989509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2361960, while the sum is 59.

The square root of 199989509 is about 14141.7647060047. The cubic root of 199989509 is about 584.7933221737.

The spelling of 199989509 in words is "one hundred ninety-nine million, nine hundred eighty-nine thousand, five hundred nine".