Numenorean Population Sizes

I was wondering how many people came to Middle Earth in the 9 ships in which Elendil and his sons escaped the downfall. How could 9 ships carry enough people (and warriors) to have founded 3 cities and to have given Sauron's forces a good fight? Were there still many Numenoreans present at the harbors that had been founded in earlier years? Did the Numenoreans join with other humans already living in Middle Earth. It's hard to imagine 1 ship carrying more than 1000 people. If there were 9000 total people aboard the 9 ships, they probably included no more than 2-3 thousand warriors. That doesn't seem like a large enough number for the war which subsequently was fought. And as long as we are talking numbers, how many elves joined in the Last Alliance? Any input would be welcomed.