Alibaba co-founder Jack Ma, who is perhaps the wealthiest person in mainland China, sold his first painting on Sunday at a Hong Kong auction for millions.

Ma painted "Paradise," an oil on canvas depicting Earth, in collaboration with his friend, renowned Chinese artist Zeng Fanzhi.

The round work sold at Sotheby's for about 42.2 million Hong Kong dollars ($5.4 million) -- 17 times more than estimated by the auction house -- to Chinese businessman Qian Fenglei, according to CNNMoney.

Proceeds from the sale will go to Paradise International Foundation, a non-profit, environmental conservation group supported by Ma, Zeng and other Chinese philanthropists and entrepreneurs.

In 2014, internet entreprenuer Ma had an estimated net worth of $29.7 billion, according to Bloomberg Billionaires Index, which ranked him as the 18th richest person in the world. His wealth has since dipped to a current estimated $21 billion.