What does a $172 million apartment look like?

According to the building's rules, the buyer has to pay cash for the $172 million apartment. Photo / Brown Harris Stevens

It is perhaps the world's most decadent deceased estate with a head-spinning $US120 million ($172 million) asking price.

The sprawling two-storey Fifth Avenue co-op apartment was home to ex-Salomon Brothers CEO John Gutfreund for decades, but since the big bank's former boss died in March at 86 the luxury unit has hit the market for the first time since the 1980s.

Sitting on the seventh and eighth floors, the duplex measures around 1115sq m and features 20 rooms making it one of the largest apartments on the prestigious Fifth Avenue strip.

Despite all those rooms, the fancy flat actually only has four bedrooms, but does include three more "staffrooms" at the far flung corners of the extreme floorplan.

But what it might lack in quantity with the bedroom count, it makes up for in quality - the main bedroom suite is 487sq m with a vast dressing room, huge sitting room, a 1930s original marble bathroom and copious cupboard space.

John Burger of Brown Harris Stevens, one of the listing agents, told the Wall Street Journal that Mr Gutfreund's widow, Susan, is selling up because the uber apartment is too large for just one person.

With three libraries and several sitting rooms, there is plenty of space for books. Photo / Brown Harris Stevens

The long list of elite features includes an entrance gallery with 7.3m high ceilings, a grand marble staircase, a 15m long living room with enviable views of Central Park, a leather-lined library (as well as an additional secret library) and that's just all on the upper level.

Downstairs there is a formal dining room that feeds onto a felt-lined butler's pantry with a walk-in steel safe just for storing silver. On top of that there is also a gigantic kitchen with all the must have Manhattan finishes.

The grand apartment hasn't changed hands since the 1980s. Picture: Brown Harris Stevens

Sneak off through the grand kitchen and laundry area and there is a whole other house-sized wing devoted to staff accommodation.

The lower level also has three more bedrooms, an office, another gallery and yet another (yes a third) library.

On title, the buyer will also get another staffroom - originally for the chauffeur - on the building's second floor as well as a wine cellar and storage space in the basement however there is no mention of a parking space.

At $157 million this is the priciest pad for sale in New York. Photo / Brown Harris Stevens

Despite the huge asking price, Mr Burger said a buyer would likely update the apartment, but added that "many people will appreciate and want to preserve the grandeur of what is there."

Designed by Rosario Candela in the early 1930s, 834 Fifth Avenue is hot property on the prestige apartment scene, so tightly held in fact its board of owners doesn't allow financing and "likes to see very strong financial credentials for any future shareholder," Mr Burger said.

- news.com.au