We have no idea whether Kushner Companies’ plan to “reinvent” 666 Fifth Ave. as a 1,400-foot-tall tower of luxury condos, a hotel and top-end retail will ever get built. My colleague Lois Weiss first reported last week that Kushner’s prospective partner, China’s Anbang, had declined to go ahead with a deal. A Kushner rep told the New York Times Monday that the company still expected to line up $2.5 billion in equity from other sources.

But, entirely separate from issues regarding Kushner’s possible conflicts of interest or the propriety of getting a Chinese cash infusion while President Trump’s son-in-law, Jared Kushner, is a close adviser to Trump are more down-to-earth matters.

One reported number is especially baffling: a $4.1 billion construction loan supposedly needed to realize late architect Zaha Hadid’s design. For a very tall but skinny tower that will have floor plates of just 10,000 square feet for most of its height?

SL Green needed only a $1.5 billion construction loan for One Vanderbilt, the highly sophisticated office tower it’s building next to Grand Central Terminal that’s 100 feet taller than a new 666 Fifth would be.

None of the World Trade Center office towers required a construction loan of more than $3 billion on sites much more complex than 666 Fifth.

And, the entire Second Avenue Subway cost $4.5 billion — including three new stations along a new, mile-and-a-half-long right of way.