The new blackjack dramedy “21,” about MIT math whizzes beating the bank in Las Vegas, stands when it should hit, never doubles down and wimps out to the point that it turns a pretty compelling tale into a bust.

It’s about bright young things who blitz casinos as a team, card counting so that they bend the odds in their favor, before cashing out and flying home winners.

And it’s a true story, or it was in Ben Mezrich’s entertaining book, “Bringing Down the House: The Inside Story of Six MIT Students Who Took Vegas for Millions.”

This slower-than-slow-handed riff on youthful idealism, a life with purpose corrupted by sudden wealth and addictive gambling, makes one wish that a single producer among the six credited had asked director Robert Luketic (“Legally Blonde”) if he’d ever seen “Ocean’s 11,” “12” or “13.” The man has no clue about how to make Vegas sexy and gambling sexier.

Kevin Spacey is the oily MIT professor who recruits working-class whiz kid Ben Campbell (Jim Sturgess, yawn) for “the team.” These underground card counters are a colorful collection of college types. Or would have been, had the script bothered to give them anything to do. The writers and director boiled Mezrich’s tempestuous squad of Asian- and Middle Eastern-looking kids (easier to explain their “wealth” at the casinos) to a whitebread package in which only a frosty Kate Bosworth (yawn again) stands out. Sort of.

Luketic takes forever to drop Ben onto the team and even longer to set up his inadequate foils, a hostile member of the team (underwritten, underplayed) and the out-of-date, old-school Vegas “consultant,” an expert (Laurence Fishburne) on card cheats who beats the tar out of people who beat the casinos.

Betrayals, misplaced loyalties, double-crosses, all are stuffed into a “21” finale that would have Danny Ocean rolling his eyes, ready to color up and blow this square version of the action in his town. He’s not alone.

Review

“21” 1 1/2 stars

Rated PG-13 (some violence and sexual content, including partial nudity)

Directed by Robert Luketic

Starring Kevin Spacey, Jim Sturgess, Kate Bosworth and Laurence Fishburne