Rihanna's absolutely glowing and grinning after her killer set at a wedding party thrown by the richest man in Asia -- and she even left the gig with some parting gifts to go along with an astronomical payday.

RiRi strolled through the Jamnagar Airport in Western India Saturday, and was clearly feeling pretty good about her performance. As we reported, she was hired to play the pre-wedding party for the son of Mukesh Ambani, the industrialist worth $112 billion.

By all accounts, he got his money's worth -- Rihanna reportedly played 17 songs on a stage fit for one of her stadium tours with all the lighting and special effects popping off around her as she belted out hits like "We Found Love" and "B**** Better Have My Money."

Hell, it might actually be a set from one of her previous concerts, judging by the massive crates of equipment she arrived with when she touched down in India.

The 1,200 friends and family of Anant Ambani and his bride-to-be Radhika Merchant didn't want to miss a second of the show as they had their phones out, recording the singer's stunning set.

BTW, the guests included scores of VIPs from around the world, including Mark Zuckerberg and wife Priscilla Chan, Ivanka Trump, Bill Gates and Google CEO Sundar Pichai.

As Rihanna made her way through the airport Saturday morning, she was carrying a giant box or bag that had "THANK YOU" printed on it.

Not that we've been in that situation, but we're guessing when you attend a party thrown by the 11th richest man in the world, everyone -- even the headliner -- leaves with a badass swag bag.

The real reason for her smile, though, is probably the direct deposit hitting her account -- she was reportedly paid $6 million for the one-night gig ... but, because the show was so long, there's speculation she even got up to 8 figures!