Benny Blanco did it big in Las Vegas for his bachelor party … staying in a swanky villa and hitting the club scene with his boys, including Lil Dicky.

Our sources tell us Benny jetted off to Sin City this past weekend with about 20 dudes … and the bachelor stayed at the sky-level villa at Resorts World.

The villa is 65 floors above the Strip and it goes for an average of $25,000 per night. The place is 5,500 square feet and it comes with all the bells and whistles, including a freaking butler.

Benny and his bros hit up XS night club at the Wynn on Saturday, where Marshmello was headlining … and Lil Dicky was among those in Benny’s group.

Selena Gomez‘s fiancé went up to the DJ booth to take a photo with Marshmello … and Benny had a VIP table.

It all sounds pretty sweet … and there’s video of Benny and his buddies raising their shot glasses in a toast before a night out on the town.

While Benny was in Vegas living it up, Selena was down in Los Cabos with a gaggle of ladies on a yacht.

Benny and Selena got engaged back in December … and it’s feeling like they may be walking down the aisle soon.