twenty-three

From Middle English twenty-thre, twenti-thre, twenti-thrie, twenty-thrie, ultimately derived from Old English þrēo and twēntiġ (“twenty-three”, literally “three and twenty”); see also three-and-twenty. The reason for the numerical swap across the spellings for all English numbers is unknown, but it may have been influenced by the Old French system, i.e. see vint trois (literally “twenty three”). By surface analysis, twenty (“the cardinal number 20, occurring after nineteen and before twenty-one”) + three (“the cardinal number 3, occurring after two and before four”).

来源：wiktionary