Question: is harry's cloak one of the deathly hallows?
Answer: Yes! The 3 deathly hallows are the invisibility cloak, the resurrection stone, and the elder wand. If a person owns all three of them, they become the master of death, which is what Harry becomes at the end of book 7. When Harry tries on the Invisibility Cloak for the first time, the only thing not covered is his head.