Last week, Epic Games officially launched its popular Fortnite game on iPhone and iPad. While the game itself is free, there are a slew of in-app purchases available to users. New data from Sensor Tower indicates that Fortnite gamers spent over $1.5 million on those in-app purchases…

The analytics company, citing its own intelligence data, says that Fortnite has generated more than $1.5 million worldwide on iOS alone, with $1 million of that coming during the first 72 hours after in-app purchases went live.

This puts Fortnite miles ahead of other mobile survival games. Knives Out, for instance, generated $57,000 during its first 4 days of availability, while Rules of Survival grossed $39,000.

As for other games on the App Store, Pokémon Go grossed $4.9 million during its first four days, while Clash Royale grossed $4.6 million. This puts Fortnite at about one-third the gross earnings of those titles.

Another thing to remember, however, is the Fortnite is still invite-only. While invites seem to be rolling at a relatively quick rate, there are still users waiting.

Fortnite launched in the App Store last Thursday to excitement from gamers everywhere. The game is wildly popular on console and PC, and the iOS version features support for cross-play, meaning users on iPhone and iPad can play against their console friends.

Have you tried Fortnite on your iOS device yet? If so, have you invested in any in-app purchases? Let us know down in the comments!