yeah, that's definitely part of the joke. Oku's part is most likely about common monetary values for yen, Narancia is just kinda stupid, and weirdly enough i'm not familiar enough with part 3 to really know what Poln's deal is (i guess he's also clueless).
Polnareff is *very* specifically saying NONprime numbers, oku doesn't get it and just randomly says numbers to see if he gets it right, along with saying "aniki" and well, yeah, it flew waaaaay above Narancia's head, who's just going "fly" and "?"
non non, Pucci's habit of prime numbers is being countered by Polnareff, who's reading non-prime numbers; Okuyasu doesn't get it and just randomly says numbers hesitantly along with "aniki", and Narancia is being a Pokemon