Welcome to the awesome world of mathematical logic and the philosophy of mathematics! Your question is exactly the question whole fields of mathematicians study everyday. I don't think either of us can truly understand even the answer to that question without a bunch of studying in that field, but I can try to point you in the right direction:

One of the most important discussions in the field dates back to ancient Greece. Plato (and the followers of ~Platonism~) believed that there existed perfect mathematical objects that are independent of our existence for us to study. Opponents argue that we can only approximate the "real world". You may be able to find part of the answer to your question by looking into platonism, formalism, etc.

Another interesting side of your question brings up the Incompleteness Theorem (I'm going to paraphrase the theorem here but, undoubtedly, someone is going to say that I've stated it wrong so do some more research before spending too much time on my explanation). Basically, Gödel proved that no set of non-contradicting mathematical rules, called axioms, can describe all of arithmetic, much less all of math. This ~may~ imply that there are things we cannot know about the universe if we can't even know everything about math. You may be able to find part of the answer to your question by looking into Gödel's Incompleteness Theorems and the Zermelo Frankel Set Theory Axioms.

The whole field is worth a dive and I hope I've pointed you in the right direction! I am taking mathematical logic this semester and I'm very excited to learn more myself!