510,000 pounds of force per engine. Every single one of these engines is comparable to a single Space Shuttle/SLS rocket engine.
(Both space shuttle and sls use solid rocket boosters to help lift them off the ground, which pack a massive punch)
With 29 Raptors, the Starship booster is the most powerful rocket stage ever manufactured. It has double the thrust of the Saturn V and significantly more thrust than the Soviet N1 Moon rocket.