199185989 has 2 divisors, whose sum is σ = 199185990. Its totient is φ = 199185988.

The previous prime is 199185979. The next prime is 199186033. The reversal of 199185989 is 989581991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 140541025 + 58644964 = 11855^2 + 7658^2 .

It is a cyclic number.

It is not a de Polignac number, because 199185989 - 2²⁰ = 198137413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199185919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99592994 + 99592995.

It is an arithmetic number, because the mean of its divisors is an integer number (99592995).

Almost surely, 2^199185989 is an apocalyptic number.

It is an amenable number.

199185989 is a deficient number, since it is larger than the sum of its proper divisors (1).

199185989 is an equidigital number, since it uses as much as digits as its factorization.

199185989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2099520, while the sum is 59.

The square root of 199185989 is about 14113.3266454086. The cubic root of 199185989 is about 584.0090746150.

The spelling of 199185989 in words is "one hundred ninety-nine million, one hundred eighty-five thousand, nine hundred eighty-nine".