What does 2 Kings 21:19 mean?

2 Kings 21:19 KJV
Amon [was] twenty and two years old when he began to reign, and he reigned two years in Jerusalem. And his mother’s name [was] Meshullemeth, the daughter of Haruz of Jotbah.

2 Kings 21:19 MKJV
Amon [was] twenty-two years old when he began to reign, and he reigned two years in Jerusalem. And his mother’s name [was] Meshullemeth, the daughter of Haruz of Jotbah.

2 Kings 21:19 NKJV
Amon [was] twenty-two years old when he became king, and he reigned two years in Jerusalem. His mother’s name [was] Meshullemeth the daughter of Haruz of Jotbah.

2 Kings 21:19 KJV 2000
Amon was twenty and two years old when he began to reign, and he reigned two years in Jerusalem. And his mother’s name was Meshullemeth, the daughter of Haruz of Jotbah.

Interlinear KJV

Amon /’Amown/ was twenty /`esriym/ and two /sh@nayim/ years /shaneh (in pl. only),/ old /ben/ when he began to reign, /malak/ and he reigned /malak/ two /sh@nayim/ years /shaneh (in pl. only),/ in Jerusalem. /Y@ruwshalaim/ And his mother’s /’em/ name /shem/ was Meshullemeth, /M@shullemeth/ the daughter /bath/ of Haruz /Charuwts/ of Jotbah. /Yotbah/

Adam Clarke’s Commentary

Verse 19.  He reigned two years in Jerusalem.] The remark of the rabbins is not wholly without foundation, that the sons of those kings who were idolaters, and who succeeded their fathers, seldom reigned more than two years. So Nadab, the son of Jeroboam, 1Ki 15:25; Elah, the son of Baasha, 1Ki 16:8; Ahaziah, the son of Ahab, 1Ki 22:51; and Amon, the son of Manasseh, as mentioned here, 2Ki 21:19.