Hollywood’s new age of realistically raunchy, female-driven romantic comedies takes a step backward with “What’s Your Number?”

If Kristen Wiig’s “Bridesmaids” was a 10 and Cameron Diaz’s “Bad Teacher” was a 6, then “What’s Your Number?” rates a 2 or 3.

As she usually does, Anna Faris comes through with a spirit and quirkiness far more engaging than the material merits, creating a character you’d like to embrace if only she wasn’t forced to behave so stupidly and shallowly. But it’s difficult to get caught up in what essentially is a one-note, feature-length gag about a woman’s sudden fixation that she’s slept around too much and that one of those former partners must have been her perfect mate.

Based on Karyn Bosnak’s novel “20 Times a Lady,” “What’s Your Number?” has Faris’ Ally Darling recently fired and fumbling romantically while everyone else seems to cruise effortlessly into love and marriage.

Ally freaks after reading an article stating that most women average 10.5 sexual partners in their lives and those who sleep with 20 or more men are prone to insecurities and low self-esteem that make them unlikely to land a husband. She tallies up her number and realizes with horror that she’s just hit that terrible milestone, so Ally vows to go without sex while she reconnects with past lovers.

It’s as episodic as it sounds as Ally and her ally — hunky neighbor Colin (Chris Evans), who conveniently has a snoop’s background — track down the men in her life one by one. The exchanges between Ally and her lovers are quick and mostly humdrum, despite a nice range of cameo appearances by such actors as Zachary Quinto, Joel McHale, Chris Pratt and Andy Samberg.

Faris’ ditzy earnestness salvages some chuckles from a few of these interactions, particularly when she lapses into a series of deteriorating accents trying to impress an old British beau.

Ari Graynor manages an easy rapport with Faris as Ally’s perfect, soon-to-be-married sister. But Blythe Danner is stuck in phony overbearing mode as their mother.

Bad as the movie is, it’s a nice showcase for Evans to display his comic charms after his superhero role in “Captain America: The First Avenger.”

From the instant Evans’ Colin appears on screen, though, it’s insipidly obvious who Ally’s Mr. Right is.

There’s a real missed opportunity for some shrewd laughs and even social insights in Ally’s conviction that 20 lovers make her undesirable while womanizing Colin, who’s clearly bedded far more partners, is simply living every guy’s dream.

“What’s Your Number?” sticks to the low common denominators of most Hollywood romances, and it ends up a commonplace one for doing so.