Not a professional so take it with a grain of salt. That’s not a warping or drying sort of split along the grain, it’s directly across the grain which would have taken a lot of force. This might be an indicator that the house is shifting or subsiding (entirely normal, but it’s a good indicator to go and have a look at your foundation).

As for the repair, sister it up like the other commenter said. You may choose to put a big carriage bolt through the cracked beam to bring it back together. Did this on a grain-split pearling beam in our loft. You can rent ceiling jacks that would help push the beam back together before bolting/sistering. Just be careful what you put the other end of the jack on - don’t go snapping a ceiling joist trying to fix this, put a big bit of 2x6 or likewise across several ceiling joists to spread the force.