prime numbers

The last few weeks I’m not thinking about prime numbers. More precisely about optimization and parallel computing when searching for them. As a result, I woke up today and began to code. In general, the warm-up for the mind is good - many ideas, I learn a lot of new things in the process of their implementation. The code crashes, debugs, searches for all large primes, crashes again, etc. And as waste remains a simple number.
Here, actually, is a question for the community - what else can we do with them with these simple numbers, except for using them to search for large prime numbers? For any ideas I will be grateful.
By the way, if anyone needs prime numbers - those that the program finds are here (this is not an advertisement, if you don’t like links, don’t go). Not yet in online mode, but this is another subtask.