777 Casino: Real Money Games 17+ - App Store

Gambling and luck 777 is used on most slot machines in the ♠ United States to identify a jackpot. As it is considered a lucky number, banknotes with a serial number containing 777 ♠ tend to be valued by collectors and numismatists.

What does 777 mean in the casino? - Quora

To play 777, follow the ♠ HOW TO WIN  instructions: Reveal a set of any three like-colored "SEVEN" symbols in a row to win ♠ the corresponding prize for that row. Reveal two sets of three like "SEVEN" symbols in a row to win double ♠ the prize.

777 | A Fast Play Game - Illinois Lottery