After the most cursory online search of “555”, I would caution against pursuing it, as it appears at first look to be an invitation to the occult. Danger lurks there for the unwary.
That being said, I proceeded with caution and found this:
In the Bible, there is insufficient use of multiple number fives, such as 555, to determine an overall meaning...So in this context, St. Peter is symbolically holding the keys to Heaven in both the forms of the Old Covenant and of the New Covenant....Multiple fives (555) confirm Moses' role as the mediator of the Old Covenant between God and the children of Israel. Deuteronomy, which is the fifth Biblical book, states the following in regards to him being an intermediary for the Israelites at Mount Sinai.