What's the largest semiprime it can factor?

You can attempt 15 yourself if you want:

https://towardsdatascience.com/where-are-we-with-shors-algor...

If you run it over and over again you will eventually get 3 or 5...

They are currently targeting more material science, such as quantum chemistry for drugs discovery or new material discovery. They can’t and do not aim to do prime factorization on those.