Do prime numbers still work in base that’s isn’t 10?

Question

I’ve started reading a lot of sci-fi and the humans always attempt to communicate with aliens using prime numbers, but if they use a counting system that _isn’t_ base10, would the prime numbers still make sense?

In: 2249

Answer 1

I feel like other comments do not address this properly.

`13` in `base15` is not a prime. Since it’s divisible by `2` in same base.

But `13` as in thirteen apples will always be a prime no matter if you write it as `13` or `D`