He was deemed a failure by Dr. Gero, who did not wish to awaken him as he was still "malfunctioning". After 17 killed the mad scientist, 18 woke 16 up out of curiosity. He surprised his fellow androids by being very single-minded, only wishing to fulfill his mission of killing Goku. Another of his personality traits is his closeness to nature, especially little animals, which he kindly lets climb on his shoulders.
He proved pivotal in defending 17 and 18 against Cell, but was eventually severely injured by the latter.
He reappeared for the Cell Games, having been repaired by Bulma Briefs, but failed to eliminate Cell due to Bulma's decision to remove his emergency self-destruction device. He was destroyed by Cell, which enabled Gohan to feel enough anger to finally fight with all his potential against the creature.
Android 16 is the one of the strongest androids in the Z series, second only to Cell. Daizenshuu 7's character bio lists him as the strongest mechanical android on the same page the Androids from the Super Android 13 film are mentioned, so 16 being stronger than Super 13 is a possibility.
16 is capable of flight, and can detach his lower arms to send a flying fist at his opponents, or blast them with his Hell Flash technique.