Install two temporary adjustable Lally columns near the middle of the beam to level it while you work. Drop a plumb bob from the center of the beam to the floor and mark it, then make that the center of a 12” square to cut out of the floor. Dig down to whatever the frost line is where you live (say, 4 feet). You can calculate how much concrete mix you should need, but I always buy more than I think the job will take, concrete mix has no expiration date. Pour about 12” into the hole, using the sides as a form (if you want to install steel reinforcement, bend it so it extends up 2 feet above this). Once that has set drop an 8” Sonotube onto it and fill it with concrete to the level of the floor. 72 hours later, level the joist with adjustable columns. Go slowly and check for cracks in the masonry above. Measure the distance from the beam to the new footing, taking base and top plates into consideration and cut a cement filled permenant Lally column to fit. I cut the pipe with a grinder and break it with a hammer. Raise the joist 1/4” or so to fit the new column, plumb it from 12 o’clock and 9 o’clock and lower the beam onto it. When you remove the temporary posts the beam should be level and solid. If the crack is bad, I would sister an LVL to it with 3/8” galvanized through bolts and washers. Next step, build a fire, crack a beer, and put on the game.