Answer based on context:

The 49ers first road game of the year ends in a disaster. The 49ers defense had no answer for Ben Roethlisberger, who went 21 for 27, 369 yards and three touchdown passes as the Steelers won 43-18. The Steelers took a commanding 29-3 halftime lead. Despite only scoring 18 points, the 49ers offense opened up in the second half, with Kaepernick leading the 49ers into the Steelers red zone four times, but only able to score one touchdown (along with a field goal and two turnover on downs). The highlight for the 49ers was Kaepernick hitting wide receiver Torrey Smith for a 75-yard touchdown pass in the fourth quarter.  The Steelers' defense had a field day on Kaepernick by sacking him 5 times and making him lose a fumble.

How many passes did Ben Roethlisberger attempt?
27