Alwaleed. a grandson of Saudi Arabia's founder, King Abdulaziz Al Saud, was being held at the Ritz-Carlton in Riyadh during his detention.
The prince does not hold a government position.
But his personal fortune is estimated at more than $17 billion, according to Forbes, and his investment portfolio has made him an important voice inside his home country.
It is not known why and under what circumstances he was released.
Three weeks after the sweep, senior Saudi Prince Miteb bin Abdullah was released, a source close to the government told CNN. An undisclosed financial settlement was agreed to secure the powerful prince's release, the source said. Prince Miteb is the son of Saudi King Salman's predecessor, the late King Abdullah.
Alwaleed got his start in business in 1979, making investments in Saudi real estate and construction. But he quickly turned to banking.
The prince captured Wall Street's attention by becoming one of Citigroup's major shareholders in 1991, a bet that would pay off handsomely. Later, when the global financial crisis caused the bank's shares to plummet, the prince increased his stake in a show of confidence. Citigroup survived.
Alwaleed has courted controversy on occasion, suing Forbes for libel in 2013 after it said he was worth only $20 billion.
In 2015, he urged Donald Trump to drop out of the presidential race, calling him a "disgrace" over threats to ban Muslims from entering the United States. In response, Trump called the prince "dopey."
In Saudi Arabia, Alwaleed advocated for giving women more freedoms, including calling for an end to a ban on driving.
ing Salmanordered the anti-corruption initiative as part of an "active reform agenda aimed at tackling a persistent problem that has hindered development efforts in the Kingdom in recent decades," a Saudi Ministry of Communications and Information Technology statement said.
After the anti-corruption arrests, the kingdom's top legal official said investigations had revealed that "at least $100 billion has been misused through systematic corruption and embezzlement over several decades."
Saudi Arabia is using cash recovered from officials and princes arrested in the crackdown to ease the pain of austerity.
The kingdom's anti-corruption committee, headed byCrown Prince Mohammed bin Salman, carried out the arrests. He is seen as a power behind the King and a supporter of reforms.
Saudi Arabia is experiencing rapid change as part of its Vision 2030 program to diversify the economy away from oil. The corruption clampdown is part of that.