Different User Levels

Hello, I am trying to establish a way to use a fmall value for defining user privileges for my system, out of our MySQL database... I would like to know what functions in PHP would allow me to do something such as: 2 = View Privilege 4 = Write Privilege 8 = Delete Privilege 16 = Edit Privilege Therefore, View + Edit would be Level (2+16) = 18. I know that there is a way of doing this, but the function name slipped my mind, and no matter for how long i stare at the PHP manual, I cannot manage to find it... any help greatly appreciated! Thanks!