Hi there. Are you a Mason talking about the numbers 3, 5, and 7 separately, or as a number itself? The three separately are of course important to Freemasonry as the 3, 5, and 7 steps leading to the Middle Chamber in the the Second Degree.
I don’t know any significance of the number itself. If somebody else does please enlighten us.
Though back in my police officer days in Texas I would hear people say, “I see you’re prone to the 357” as a little test to see if they might be a Mason. I wasn’t one then so I always said “No, it’s a 41, but I’m really more of a 45 guy”