I'm assuming in Python 2, 9/4 = 2, but 9.0/4.0 = 2.25.

wait what? then how did Python 2 divide normally?

No, 117 = 3313 and 117 ** 0.5 is about 10, so if you break the while loop, you won't find 13! But if you want to find out is a number prime, that will help.

If you do p.append([m,1]) break the while loop when i ** 2 > m it will be faster.

Please use spoiler flag next time.

Yeah, this needs memoization. Lots of repeated calculations. Super inefficient.

сould someone please explain me why {6,}$
not {3,}$ ???

Huh? Surely it doesn't work, as it doesn't return an integer. Am I missing something?

Why import itertools every time def is called...

nice one

Why recursive lambda?
It is generaly not a good practice to try to make the code as short as possible but to make it as readable as possible...
For example if you look at my solution, it is basicaly the same as yours but a lot more readable.
(Just a tip :))

Damn, that's really good. It's exactly what I was thinking of... but so much simpler.

no need to check if word exists

Doesn`t work for sure :)