Japanese
Japanese uses different words for small numbers depending on what you're counting. the words for the numbers up to six are different if you're just talking about the numbers themselves,
0: れい (rei)
1: いち (ichi)
2: に (ni)
3: さん (san)
4: よん (yon)
5: ご (go)
10: ろく (roku)
if you're counting objects,
1: ひとつ (hitotsu)
2: ふたつ (futatsu)
3: みっつ (mittsu)
4: よっつ (yottsu)
5: いつつ (itsutsu)
10: むっつ (muttsu)
if you're counting people,
1: ひとり (hitori)
2: ふたり (futari)
3: さんにん (sannin)
4: よにん (yonin)
5: ごにん (gonin)
10: ろくにん (rokunin)
if you're counting days,
1: いちにち (ichinichi)
2: ふつか (futsuka)
3: みっか (mikka)
4: よっか (yokka)
5: いつか (itsuka)
10: むいか (muika)
if you're counting nights,
1: いっぱく (ippaku)
2: にはく (nihaku)
3: さんぱく (sanpaku)
4: よんはく (yonhaku)
5: ごはく (gohaku)
10: ろっぱく (roppaku)
if you're counting floors,
1: いっかい (ikkai)
2: にかい (nikai)
3: さんかい (sankai)
4: よんかい (yonkai)
5: ごかい (gokai)
10: ろっかい (rokkai)
or if you're counting how old someone is.
1: いっさい (issai)
2: にさい (nisai)
3: さんさい (sansai)
4: よんさい (yonsai)
5: ごさい (gosai)
10: ろくさい (rokusai)
in this situation, we're talking about the numbers themselves, so we'll be using the first set of words.
numbers after six can be formed the same way Japanese forms numbers after ten, by saying the amount of sixes, the word ろく, and then the amount of ones.
11: ろくいち (roku ichi)
12: ろくに (roku ni)
13: ろくさん (roku san)
14: ろくよん (roku yon)
15: ろくご (roku go)
20: にろく (niroku)
21: にろくいち (niroku ichi)
30: さんろく (sanroku)
40: よんろく (yonroku)
50: ごろく (goroku)
Japanese is VERY okay with using loanwords.
100: ニフ (nifu)
101: ニフいち (nifu ichi)
110: ニフろく (nifu roku)
111: ニフろくいち (nifu roku ichi)
200: にニフ (ni nifu)
1 0000: ウーネクシアン (ūnekushian)
1 0000 0000: バイエクシアン (baiekushian)