BOSTON, Oct 10 (Reuters) - Lookout, one of the world's biggest providers of mobile security software, said on Thursday that it has raised $55 million in financing.

The round was led by Deutsche Telekom AG DTEGn.DE .

Qualcomm Inc's QCOM.O venture capital arm, Greylock Partners and Mithril Capital Management also participated, as did current investors Accel Partners, Andreessen Horowitz, Index Ventures, and Khosla Ventures.

Lookout's security software is installed on some 45 million devices running Google Inc's GOOG.O Android operating system and Apple Inc's AAPL.O iOS.

Telecommunications firms such as Deutsche Telekom and Qualcomm are growing increasingly interested in mobile security products because cyber attacks on mobile devices have grown exponentially in recent years as sales of smartphones and tablets have surged to consumers and businesses alike.

Lookout said in a statement that it plans to enter the corporate security market later this year, which would put it in competition with older, more established software makers including Symantec Corp SYMC.O and Intel Corp's McAfee security division.

San Francisco-based Lookout, founded in 2007, has raised $131 million to date.

(Reporting by Jim Finkle; Editing by Nick Zieminski)

((jim.finkle@thomsonreuters.com)(+1 617-856-4344)(Reuters Messaging: jim.finkle.thomsonreuters.com@reuters.us))

Keywords: LOOKOUT/FUNDING