"Catch 22" refers to the military Catch 22 in the book: If you were crazy, you did not have to fight. But you did have to ask to be exempted. If you asked to be exempted, you weren't considered crazy.
The title refers to illogical bureaucratic rules experienced by the main character. Originally, it was to be named Catch-18, but was changed to avoid confusion with another recently published novel.
The title number has no real significance. In fact the author and publisher decided at the end. The phrase now means that either major choice has bad consequences.
The phrase catch 22 means a no-win situation. I have not read the book, but it possibly refers to that there is no beneficial possible outcome in the book.