In 2009, running for a third term as mayor, Michael Bloom­berg spent $102 million to get a mere 51%, total of $174 per vote. If he were to spend $174 per vote in this bid for the presidency in 2020 we’re hearing so much about, the White House would cost him something like $12 billion.

Google tells me Bloom­berg is worth $53 billion. Buying the presidency would take about a quarter of his wealth. So why not run? He only has two kids. Do they really need the full $53 billion after he sloughs off this mortal coil when they could split $41 billion?

If Bloomberg wants it, why shouldn’t he try to buy it? This is America, people! We all like to say things like “the presidency is not for sale,” but have we ever really truly tested the proposition?

Besides, enormously rich people like Bloomberg help support our economy by putting dollars into play. When it comes to electoral politics, he’s is a one-man money velocity machine.

This presidential run is a full-employment measure for a certain type of political and media player — you know, the kind who likes to earn money.

And not just people who work to get him elected. Bloomberg bucks will also enrich the coffers of TV networks, local channels in battleground states, social media companies and all those still dreaming that web advertising will someday make their sites profitable. (Bloom­berg could make it happen!)

And think of all the liberal and leftist organizations to which he gave generously as a philanthropist and who then remained mysteriously quiet when he did things to which they would have objected vociferously if anyone else had been mayor. He did it before; he could do it again.

If I were you, I’d file papers to open a not-for-profit Trans-Latinx Coalition for Gun Control and Climate Change as soon as possible. It’s gold, Jerry, gold!

The only aspect of Bloom­berg’s newest “I’m gonna do it, watch me, this time I’m really going to run” trial balloon that makes no sense is that he intends to run as a Democrat.

Granted, he’s a gun-control maniac and a climate-change hysteric, which should make him minimally palatable to certain Democratic constituencies.

But he is also Mr. Stop-and-Frisk, which wouldn’t. And he’s a billionaire many times over, which doesn’t bother me but does bother a great many Democratic voters. Bernie Sanders has even said that “there should be no billionaires.”

With the money he could spend, Bloomberg could actually fund a realistic third-party candidacy that might represent the first real political opening for a political-electoral movement that is neither Democratic nor Republican in 150 years. He could help build an apparatus that could live on after him.

That would be a visionary play. The problem is that, aside from having this one amazing idea about putting proprietary stock-ticker machines on every trader’s desk back in the Dark Ages of the early 1980s, Bloom­berg doesn’t seem to have much in the vision department. That’s why he may run for president when he doesn’t have a chance of winning.

Or does he? As William Goldman said of Hollywood, “Nobody knows anything.” About 14 people in America thought Donald Trump would be president before he came down the escalator, and look where we are now.

Not to mention that if you’d said in November 2016 the choice in the Democratic field would be between the front three of the Junior Varsity Shuffleboard Team at the Del Boca Vista Condo and their very nice, well-spoken nephew, ­everybody would have called you crazy.

So go for it, Mike Bloomberg. You have nothing to lose but … really, nothing. For all we know, by the time you spend that $12 billion, your wealth level will be back up to $53 billion without it. It’s fun being rich.