The entity started by Facebook CEO Mark Zuckerberg and his wife, Priscilla Chan, to tackle big global problems is growing more like a tech start-up than a typical charitable organization.

A review of the Chan Zuckerberg Initiative's website and other online pages indicates it has just over 160 employees, with open positions for 38 — numbers confirmed by a source close to the organization.

That's just 20 months after its founding in December 2015.

The number of engineers has exploded during the past year, surging from just three people to nearly 100.

And Chan Zuckerberg looks set for another fresh infusion of cash, after Mark Zuckerberg sold a large amount of Facebook shares this week earmarked for his these efforts.

He sold at least $25.5 million worth, according to a company securities filing, on top of the $32.5 million sold last month for the benefit of the Chan Zuckerberg Foundation and CZI Holdings.

That's a drop in the bucket compared with the billions of dollars Zuckerberg and Chan have pledged toward the organization, whose mission is "advancing human potential and promoting equality."

The couple pledged to donate $1 billion a year toward it, and last year created a new investment vehicle, Chan Zuckerberg Science, that will put $3 billion toward the lofty goal "to help cure, manage or prevent all disease by the year 2100."

That's not the only big problem Chan Zuckerberg has taken on.

In an 'Ask Me Anything' session on the discussion website Reddit this week, a group of Chan Zuckerberg scientists said they're working on the Human Cell Atlas project.

That's a global effort to map all 30 trillion cells in the human body, similar to how the human genome project identified genes.

Its ambitions and deep pockets aren't the only things that make the Chan Zuckerberg organization unique.

It's also organized as an LLC, not a nonprofit foundation. While that eliminates any tax benefits for Zuckerberg — one of the world's wealthiest people — it also gives the initiative more flexibility on how to spend it, as he explained in this post. Zuckerberg has pledged to plow any profits from investments back into the initiative to advance its mission.

Zuckerberg devotes one day a week toward the effort, while Chan spends more time there.

All of which means something may have to give if, as has been widely speculated, Zuckerberg should decide to use another portion of his fortune to finance a political career.