198908009 has 2 divisors, whose sum is σ = 198908010. Its totient is φ = 198908008.

The previous prime is 198907963. The next prime is 198908023. The reversal of 198908009 is 900809891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 181710400 + 17197609 = 13480^2 + 4147^2 .

It is a cyclic number.

It is not a de Polignac number, because 198908009 - 2²⁰ = 197859433 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (198908609) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99454004 + 99454005.

It is an arithmetic number, because the mean of its divisors is an integer number (99454005).

Almost surely, 2^198908009 is an apocalyptic number.

It is an amenable number.

198908009 is a deficient number, since it is larger than the sum of its proper divisors (1).

198908009 is an equidigital number, since it uses as much as digits as its factorization.

198908009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 44.

The square root of 198908009 is about 14103.4750682234. The cubic root of 198908009 is about 583.7372709894.

The spelling of 198908009 in words is "one hundred ninety-eight million, nine hundred eight thousand, nine".