As the song says “One is the loneliest number that you’ll ever do.”
Although I think a case could be made for zero being even more lonely a number. Zero is certainly the roundest number, in one sense.
So… make your case for X being the something-est number - where X is a number of your choice, and you explain the ‘something’.
I’ll start with 9. I think 9 could be the squarest number. Sure, there are any number of squares, and 9 is not the first, but as a square, 4 only has corners - 9 has edges and a middle (If visualised as a square of 9 points) - 16 doesn’t - and although 25 does, it doesn’t do it any more stylishly and simply than 9.
(subjectivity is fine, as long as you can explain it)
So - what are the sharpest, smoothest, greenest, hottest, fastest, or anthing-else-est numbers, and why?
4 is the greenest number - I’m not sure why it seems so “green” to me, but it could be that shamrocks are green and have 4 leaves. 5, on the other hand, is hot pink, and is the warmest number.
10 is the most stable number, because it’s our base.