199909109 has 4 divisors (see below), whose sum is σ = 199938816. Its totient is φ = 199879404.

The previous prime is 199909097. The next prime is 199909141. The reversal of 199909109 is 901909991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 901909991 = 3943 ⋅228737.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199909109 is a prime.

It is a super-2 number, since 2×199909109² = 79927303722347762, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199909159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 602 + ... + 20004.

It is an arithmetic number, because the mean of its divisors is an integer number (49984704).

Almost surely, 2^199909109 is an apocalyptic number.

It is an amenable number.

199909109 is a deficient number, since it is larger than the sum of its proper divisors (29707).

199909109 is a wasteful number, since it uses less digits than its factorization.

199909109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29706.

The product of its (nonzero) digits is 59049, while the sum is 47.

The square root of 199909109 is about 14138.9217764298. The cubic root of 199909109 is about 584.7149452539.

The spelling of 199909109 in words is "one hundred ninety-nine million, nine hundred nine thousand, one hundred nine".