199989989 has 4 divisors (see below), whose sum is σ = 211754124. Its totient is φ = 188225856.

The previous prime is 199989983. The next prime is 199990013. The reversal of 199989989 is 989989991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 86397025 + 113592964 = 9295^2 + 10658^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199989989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199989983) 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, 5882042 + ... + 5882075.

It is an arithmetic number, because the mean of its divisors is an integer number (52938531).

Almost surely, 2^199989989 is an apocalyptic number.

It is an amenable number.

199989989 is a deficient number, since it is larger than the sum of its proper divisors (11764135).

199989989 is a wasteful number, since it uses less digits than its factorization.

199989989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11764134.

The product of its digits is 34012224, while the sum is 71.

The square root of 199989989 is about 14141.7816770024. The cubic root of 199989989 is about 584.7937900326.

The spelling of 199989989 in words is "one hundred ninety-nine million, nine hundred eighty-nine thousand, nine hundred eighty-nine".