At Tesla's Texas factory, shareholders chanted "Elon, Elon" as they overwhelmingly approved the largest-ever CEO compensation package for the company's controversial boss.

More than 75 per cent of the shares were voted in favour of the deal for Elon Musk, who walked on stage and dropped a few dance moves alongside a humanoid robot before telling the small crowd, "I super appreciate it".

If Musk delivers on the full terms of the deal he will take control of about a quarter of the company and increase Tesla's market value by trillions of dollars.

The vote has garnered huge attention, not just because of Musk's personal (often controversial) profile, or how unusual it is for a company board engage in such public lobbying, but because of the eye-watering fact that it puts Musk on track to become the world's first trillionaire in the next decade.

What is a trillionaire?

It's a tricky question, because in reality there hasn't been one before — Musk would be the first if he hits the milestones outlined in the pay deal.

A trillion is equal to a thousand-billion — that is a number with 12 zeros: $1,000,000,000,000.

And Tesla obviously operates in US dollars, so we're talking $US1 trillion, which would be $AUD1.54 trillion.

That's more than half the value of Australia's economic output last year, which was $US1.75 trillion ($2.7 trillion), according to the World Bank.

In October, Musk became the world's first half-trillionaire and, onc