The premises of the questions are wrong, hence they do not speak to the knowledge of anyone but yourself unfortunately. There are no last element in an infinite chain, because that is contradictory to the fact that they are infinite. Even questions such as the barber's paradox, that are not logical fallacies, do not imply the nonexistence of god.

Mathematically speaking, everyone knows the last digit in Pi due to there not being one. We call this concept that something is vacuously true. Similarly a nonsense statement such as "all ants on the moon eat people for breakfast" is also true by default.

so the proof of the irrationality of pi is a bit more than i want to get into here, but there's a very simple proof that there are infinite prime numbers which i will share here.

suppose that there is a finite number of prime numbers. write out a list of all of these prime numbers, and multiply them together. add one to this product, and you now have a number that is not divisible by any of our list of prime numbers, and thus should be another prime. this contradicts our initial assumption of finite primes, and therefore there are infinite primes.

any god is not above mathematics.

Knowing they don't exist would count.