• Flashy young founders may get a lot of attention, but the typical billionaire is older than you may think.

• The median age of the world's billionaires is 67, according to a new report from Altrata.

• Younger billionaires are more likely to make their money in tech — or through inheritance.

Young billionaires like Elon Musk and Kim Kardashian may capture public attention with their online antics, flashy purchases, and high-flying lifestyles, but the average billionaire looks a lot less like Rihanna and a lot more like your grandparent.

The median age of the world's billionaires is 67, according to a new report from data firm Altrata. Only 10% of the world's billionaires are younger than 50 — and over 40% are older than 70.

A lot of this has to do with the sheer fact that it takes a while to amass $1 billion, whether that wealth is from smart investing — public holdings make up the largest share of billionaire portfolios across all ages — or from a single successful company.

While finance is the most popular source of wealth for billionaires of all ages, technology is becoming a more common ticket into the three-comma club, Altrata found.

"Among billionaires aged under 50, technology ranks a close second in importance, followed by business and consumer services, and hospitality and entertainment," the study says. "None of these appear in the leading industries for billionaires aged 70+."

Another source of wealth among young billionaires? Inheritance. Billionaires under 50 are twice as likely to have inherited their wealth compared with the over-50 set.

Billionaires, for what it's worth, don't seem ignorant to the fact that they are an older breed. Many are using their money to fund the quest for eternal life — or at least a longer one.

Peter Thiel has invested in organizations that focus on cryonics, or the practice of freezing human corpses to stop the aging process, and Jeff Bezos has reportedly poured money into a biotech startup that seeks to "reverse disease, injury, and the disabilities that can occur throughout life."