Google appears close to buying the trophy 111 Eighth Ave. building, one of the largest buildings in Manhattan, The Post has learned.

The price is rumored to be tantalizingly close to $2 billion.

The 18-story Chelsea giant carries 2.9 million square feet of space and covers an entire city block — between Eighth and Ninth avenues from 15th and 16th streets.

At that price, the sale works out to around $690 per square foot, very respectable for 2010 but far less than the $1,500 a square foot that was commonplace in the heady days of 2007.

Google has made no secret of its growth plans for the Big Apple and already rents over 550,000 square feet in the building — considered the premier tech, entertainment, fashion, and media center in the city with tenants ranging from Nike to WebMD.

Sellers Taconic Partners, Jamestown and the New York State Common Retirement Fund had hoped to recapitalize the building. As The Post previously reported, the group has been marketing it through investment adviser Douglas Harmon of Eastdil Secured.

It is not yet clear if the current owners are bailing out or staying in with a small piece of the equity. Google declined to comment in an e-mail, while none of the other parties returned calls or e-mails.

Sources said Google officials are already searching the city’s top real-estate law firms for someone to represent them in the massive purchase.

The deal could still change or fall apart. It could not be determined if a contract has been signed or if there is just a handshake.

As a former Port Authority of New York and New Jersey industrial property, 111 Eighth Ave. has numerous back-up generators, lots of electrical power, antennas, fiber optics and high-tech facilities available to tenants.

The owners modernized the building with 10-foot tall windows and a modern lobby with glowing glass disks, along with 24/7 security and a concierge. It is 98.7 percent leased and parking is available in the building, according to CoStar, a real-estate information firm.

Several sources said Google was only one of many interested bidders, including local families, real-estate investment trusts, overseas entities from Beijing, Singapore, Chile, Argentina and Israel, along with sovereign wealth funds from the Middle East and Asia.

“The world has been waiting for the right type of asset,” said one source on the level of interest that was generated.