the kind of architecture mentioned, does any other structure have the same?
Yes, the Willis Tower's and the John Hancock Center's.
Exterior
The amount of material used in the building's construction resulted in a very stiff structure when compared to other skyscrapers, with a structural stiffness of versus the Willis Tower's and the John Hancock Center's .
how many floors is the empire state building observation deck 3 floors. where is it located? Midtown Manhattan in New York City. what is the earlier mentioned building used for? UNANSWERABLE what kind of architecture does it follow? Pre–World War II architecture. did the design have any kind of change? Yes, it was later increased to 60 and then 80 stories. the place where you mentioned it is located, what is it's economics? It, along with Lower Manhattan, is one of the world's leading financial centers. does it have any kind of headquarters? Midtown contains the headquarters of major companies, including 4Kids Entertainment (formerly), Barnes & Noble, Bloomberg L.P. to name a few.
Yes, the American Radiator Building, Detroit's Guardian Building, Chrysler Building etc. Yes, the Twin Towers UNANSWERABLE
Art Deco Empire State Building
Skyscrapers Loss of "tallest building" title
 The American Radiator Building by Raymond Hood (1924) combined Gothic and Deco modern elements in the design of the building. Black brick on the frontage of the building (symbolizing coal) was selected to give an idea of solidity and to give the building a solid mass. Other parts of the facade were covered in gold bricks (symbolizing fire), and the entry was decorated with marble and black mirrors. Another early Art Deco skyscraper was Detroit's Guardian Building, which opened in 1929. Designed by modernist Wirt C. Rowland, the building was the first to employ stainless steel as a decorative element, and the extensive use of colored designs in place of traditional ornaments.

The New York skyline was radically changed by the Chrysler Building in Manhattan (completed in 1930), designed by William Van Alen. It was a giant seventy-seven-floor tall advertisement for Chrysler automobiles. The top was crowned by a stainless steel spire, and was ornamented by deco "gargoyles" in the form of  In December 1975, the observation deck was opened on the 110th floor of the Twin Towers, significantly higher than the 86th floor observatory on the Empire State Building. 
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Empire State Building [SEP] Exterior
The Empire State Building's art deco design is typical of pre–World War II architecture in New York. The modernistic, stainless steel canopies of the entrances on 33rd and 34th Streets lead to two-story-high corridors around the elevator core, crossed by stainless steel and glass-enclosed bridges at the second-floor level. The riveted steel frame of the building was originally designed to handle all of the building's gravitational stresses and wind loads. The exterior of the building is clad in Indiana limestone panels sourced from the Empire Mill in Sanders, Indiana, which give the building its signature blonde color. The amount of material used in the building's construction resulted in a very stiff structure when compared to other skyscrapers, with a structural stiffness of versus the Willis Tower's and the John Hancock Center's .