The anti-Obama documentary "2016: Obama's America" began showing in more than 1,000 theaters nationwide on Friday, more than any political documentary in the past eight years, since Michael Moore's 2004 film "Sicko" was released in 1,117 theaters.

"2016," which argues that President Obama's father's Kenyan roots have led the president to take an anti-American world view, has grossed more than $2.6 million since it was first released in Houston last month. The film is now the eleventh highest-grossing political documentary in history, according to Box Office Mojo, which tracks movie ticket sales.

"Demand has driven the expansion a 'little' fast[er] than I had planned but the early morning numbers from theaters is telling me 2016 is going to have a nice weekend at the box-office," Randy Slaughter, a spokesman for the film's distributor Rocky Mountain Pictures, said in an email.

While reviews of the film have been less than glowing - Variety's Joe Leydon dubbed it a "a cavalcade of conspiracy theories, psycho-politico conjectures and incendiary labeling" - a several big-name conservatives have endorsed the highly-critical look at Obama's past.

On Friday, Donald Trump tweeted about movie, based on conservative author Dinesh D'Souza's book "The Roots of Obama's Rage," predicting it "will be highest grossing documentary in 2012!!"

Former GOP presidential candidate and Texas Gov. Rick Perry tweeted his endorsement of the film when it opened in his state on July 13.

"Strong opening day for 'Obama's America,'" Perry tweeted. "This summer's must see movie!!"

Conservative radio host Rush Limbaugh has mentioned the film at least three times over the past month, saying it shows "exactly what I've told you from the get-go, that Obama has a chip on his shoulder about this country, that it's illegitimate, it's immoral, its founding was unjust, and it's his role, it's his job to cut this country down to size 'cause that's what this country deserves."

Rachel Rosen, the director of programming at the San Francisco Film Society, said the film has probably succeeded because of its ability to "catch the zeitgeist of what people are thinking about."

In this case that zeitgeist is the conservative skepticism about President Obama's multinational childhood. Obama was born in Hawaii to a mother from Kansas and a father from Kenya and grew up in Hawaii and Indonesia.

"This man's background deeply illuminates his policy priorities," D'Souza, who co-directs and stars in the film, told ABC News after its release in July. "He subscribes to an ideology that sees America very differently."

Frederic Lahey, director of the Colorado Film School, said the film has likely seen such popularity because it is "emotionally evocative" and ends with a "call to action." Lahey said documentaries are becoming more popular because people are "encountering lots of frustration in their lives" and "are looking for solutions and fresh perspective."

"Too often the entertainment films are like eating a candy; once it's gone it's gone and unless it was tremendously well made the taste can be a little too sugary," Lahey said. "Sometimes people are looking for a meal, something with a little more protein and content."