Question: "What are archangels? Is Michael the only archangel?"
Answer: The word archangel occurs in only two verses of the Bible. 1 Thessalonians 4:16 exclaims, "For the Lord Himself will come down from heaven, with a loud command, with the voice of the archangel and with the trumpet call of God, and the dead in Christ will rise first." Jude verse 9 declares, "But even the archangel Michael, when he was disputing with the devil about the body of Moses, did not dare to bring a slanderous accusation against him, but said, 'The Lord rebuke you!'" The word archangel comes from a Greek word meaning "chief angel." It refers to an angel who seems to be the leader of other angels.
Michael is the only angel identified as an archangel (Jude verse 9). However, Daniel 10:13 describes Michael as "one of the chief princes." This possibly indicates that there is more than one archangel, because it places Michael on the same level as the other "chief princes." Daniel 10:21 describes Michael the archangel as "your prince," and Daniel 12:1 identifies Michael as "the great prince who protects." So, while it is possible that there are multiple archangels, it is best not to presume upon the Word of God by declaring other angels as archangels. 1 Thessalonians uses the singular to identify "the voice of THE archangel," not "the voice of AN archangel," which would allow for the possibility of there being more than one archangel. Even if there are multiple archangels, it seems that Michael is the chief among them.