Why is the American moon landing program called "Apollo" and named after the sun god?

In ancient Greek mythology, Apollo was the sun god (also the god of youth, light, music, art, medicine and prophecy), his father was Zeus, the king of gods, his mother was Leto, and Apollo had a twin sister, the moon and the goddess of hunting, themis. Therefore, the moon landing program was named Apollo program, which may have the relationship between Apollo and themis, and was inspired and influenced by myths.