The Extell Development Company this week launched its marketing campaign for The Rushmore, a condominium apartment tower on Upper West Side property it recently acquired from Donald Trump and a consortium of investors from Hong Kong.

The new project is located at Riverside Boulevard and 64th Street and presumably will have a 80 Riverside Boulevard address since it is one block south of the Avery at 100 Riverside Boulevard on which Extell only began marketing this year. The Avery is a 32-story building with 274 condominium apartments priced from about $850,000 to more than $3,000,000.

An advertisement in Quest, a monthly magazine that was distributed yesterday, indicated that one- to five-bedroom apartments at The Rushmore will range from approximately $1,000,000 to over $6,000,000. No indication was given of how many stories The Rushmore might have, or how many units, but presumably it will about the same size as the Avery.

The building will have twin towers atop a seven-story base and has been designed by Costas Kondylis.

The Rushmore will have a 24-four concierge and doorman, a garage, a swimming pool, an atrium with adjacent reading room, a "Grand Salon with catering capabilities," a billiards room, a "Kid's Creative Studio and Playroom, a La Palestra Spa & Fitness Center, and "Abigail Michaels lifestyle managers, a member of Les Clefs d'Or."

Extell and the Carlyle Group paid about $1.8 billion recently to acquire 20 acres between 59th and 65th Streets from Donald Trump and a consortium of investors from Hong Kong who have been developing properties to the north along Riverside Boulevard that ends at 72nd Street.

Extell and Carlyle are expected to erect six buildings on their property that overlooks the West Side Highway and the Hudson River.

Extell has recently become one of the city's most active developers. Some of its other projects include the Orion on West 42nd Street, the Ariel East and West on Broadway at 99th Street, Altair 18 and Altair 20 in Chelsea, the W. Hotel in Times Square.