What does it mean for a number to be "discovered"?
Is the number 689160670188354570499 discovered, for example? It is a number I just came up with. Any computer can verify extremely quickly (immediately, to a human) that it is a prime. It is not very interesting. It has 21 figures, and it is almost certain that no person has ever considered that number before.
But it is not worth calling the fact that I am talking about this number, "a discovery". It is just a number.
"A discovery" must be something people consider interesting and worth putting a lot of effort into searching for, or something that is unexpected (e.g. a number with a property people did not expect to exist).