I didn't get a message telling me h34 had posted for 51 while I was writing up my post, so I'll leave it, since our languages don't overlap, and post again for 52.
51 五十一 (ごじゅういち)
limapuluh satu
kanalimakūmākahi
ashdladiin dóó baʼąą tʼááłáʼí
naanimidana-ashi-bezhig
cincuenta y uno
cinquanta-u
cinquante et un
hanner cant ac un; pum deg un
unan hag hanter-kant
aon air leth-cheud; dà fhichead 's a h-aon deug; caogad ’s a h-aon*
caoga a haon
एकपञ्चाशत्
ekapanchaashat femtioett
*those are just the three most common ways to say 51 in Scottish Gaelic. There are other possible ways that aren’t as much part of common usage but still grammatically correct. It’s just with 51 through 59, Scottish Gaelic goes a little nuts with possibilities. It gets nuts when you get close to 100 too, with constructions like "ceud ach dhà" which literally translates as "hundred but (minus) two," for 98, in additional to expected vigesimal and decimal forms.