Tesla Motors CEO Elon Musk. REUTERS/Rebecca Cook Elon Musk may have a net worth upward of $13 billion, but he is not above hitting up his friends to crash in their spare bedrooms.

Musk owns a $17 million home in Los Angeles with gorgeous ocean views, but he doesn't have any property in Silicon Valley, where his company Tesla Motors is based.

"He's kind of homeless, which I think is sort of funny," Google CEO Larry Page told Ashlee Vance for Vance's soon-to-be-released book, "Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future."

When Musk visits every week, he sometimes pings Page, who owns a six-bedroom home in Palo Alto as well as a second eco-friendly mansion on the same property.

"He'll e-mail and say, 'I don't know where to stay tonight. Can I come over?'" Page says. "I haven't given him a key or anything yet."

You can read more nuggets from Vance's book thanks to The Washington Post's Matt McFarland, who put together a list of its top quotes.