199988609 has 4 divisors (see below), whose sum is σ = 200016900. Its totient is φ = 199960320.

The previous prime is 199988603. The next prime is 199988653. The reversal of 199988609 is 906889991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 146289025 + 53699584 = 12095^2 + 7328^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199988609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (199988603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6617 + ... + 21065.

It is an arithmetic number, because the mean of its divisors is an integer number (50004225).

Almost surely, 2^199988609 is an apocalyptic number.

It is an amenable number.

199988609 is a deficient number, since it is larger than the sum of its proper divisors (28291).

199988609 is a wasteful number, since it uses less digits than its factorization.

199988609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28290.

The product of its (nonzero) digits is 2519424, while the sum is 59.

The square root of 199988609 is about 14141.7328853292. The cubic root of 199988609 is about 584.7924449364.

The spelling of 199988609 in words is "one hundred ninety-nine million, nine hundred eighty-eight thousand, six hundred nine".