Rapper, producer and businessman Dr. Dre tops this year's Forbes list of highest-paid hip hop acts, according to the business magazine.

With his earnings from Apple's $3 billion purchase of Beats Electronics, the high-end headphone company he co-founded with record executive Jimmy Iovine, the rapper's wealth is estimated at $620 million.

After the announcement of the company's sale, the rapper was quick to call himself hip hop's first billionaire, according to Forbes. This didn't turn out to be the case, however, as the tax for the purchase was a nine-figure bill.

In addition to Beats, Dr. Dre has other financial investments which have contributed to his earnings, including cognac and vodka brands.

The takings of Dr. Dre, whose real name is Andre Romelle Young, between June 2013 and 2014 are the highest of any musician in any genre Forbes has estimated, according to Billboard. They're also more than the combined earnings of the other 24 hip hop artists on Forbes' list, dubbed "Hip Hop Cash Kings," released on Tuesday.

The 49-year-old rapper has raked in far more than the second placers, rappers and businessmen Sean "Puff Daddy" Combs and Jay-Z, who have each earned $60 million.

Combs, 44, was last year's top earner with $50 million. He has investments in drinks and clothing and has earned from television deals.

Meanwhile, Jay-Z, whose real name is Shawn Parker, has made money from hugely profitable concerts and running his entertainment company Roc Nation.

Rapper Drake, 27, is the fourth on the list, with $33 million partly from his album "Nothing Was the Same," an endorsement deal with Nike and a concert tour.

Just behind him is the duo Macklemore and Ryan Lewis, with $32 million.

Forbes built the list after referring to record sales, publishing, merchandise sales, tours and endorsement deals, according to The Guardian. The magazine also consulted with managers, agents, lawyers and some of the artists.

The earnings were computed based on data given by Pollstar, Recording Industry Association of America (RIAA) and Nielsen Soundscan.