'Twenty first' in the Bible

You are to eat unleavened bread in the first month, from the evening of the fourteenth day of the month until the evening of the twenty-first day.

the twenty-first to Jachin, the twenty-second to Gamul,

the twenty-first to Hothir, his sons, and his brothers—12

On the twenty-first day of the seventh month, the word of the Lord came through Haggai the prophet: