199909989 has 24 divisors (see below), whose sum is σ = 294983832. Its totient is φ = 130429440.

The previous prime is 199909961. The next prime is 199909991. The reversal of 199909989 is 989909991.

It can be written as a sum of positive squares in 4 ways, for example, as 56700900 + 143209089 = 7530^2 + 11967^2 .

It is not a de Polignac number, because 199909989 - 2⁷ = 199909861 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199909909) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88899 + ... + 91119.

It is an arithmetic number, because the mean of its divisors is an integer number (12290993).

Almost surely, 2^199909989 is an apocalyptic number.

It is an amenable number.

199909989 is a deficient number, since it is larger than the sum of its proper divisors (95073843).

199909989 is a wasteful number, since it uses less digits than its factorization.

199909989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2437 (or 2434 counting only the distinct ones).

The product of its (nonzero) digits is 4251528, while the sum is 63.

The square root of 199909989 is about 14138.9528961660. The cubic root of 199909989 is about 584.7158032244.

The spelling of 199909989 in words is "one hundred ninety-nine million, nine hundred nine thousand, nine hundred eighty-nine".