24th day of the month
Only with reading にじゅうよっか
Standard date expression; the reading にじゅうよっか is the only natural one for this meaning.
The meeting will be held on the 24th.
24 days
Used for a duration of 24 days; the reading にじゅうよっか is standard, while にじゅうよんにち and にじゅうよにち are irregular but sometimes heard.
This medicine is for 24 days.
Abbreviated kanji form; rarely used.