Question 16The number $21!$ $= 51{,}090{,}942{,}171{,}709{,}440{,}000$ has over $60{,}000$ positive integer divisors. One of them is chosen at random. What is the probability that it is odd?$\dfrac{1}{21}$$\dfrac{1}{19}$$\dfrac{1}{18}$$\dfrac{1}{2}$$\dfrac{11}{21}$