２４にじゅうよ時じ間かん

に

じゅ

う

よ

じ

か

ん

Meanings

1

24 hours; twenty-four hours

A period of exactly one full day; used in contexts like business hours, marathon events, or continuous operation.

This shop is open 24 hours.

２４時間にじゅう以内よじかんいないに返へん事じをください。

Please reply within 24 hours.

一いち日にち
一日 means 'one day' as a calendar day or daytime, while ２４時間 emphasizes the exact duration of 24 hours.
終しゅう日じつ
終日 means 'all day long' and is more formal/literary, often used in written announcements.

２４にじゅうよ時じ間かん
Commonly written with Arabic numerals; the most frequent spelling in modern Japanese.
二に十じゅう四よ時じ間かん
Kanji spelling; less common but still used, especially in formal or vertical writing.

Compound of 二十四 (twenty-four) and 時間 (hours). A straightforward numerical expression.