The success that Fortnite is currently achieving is absolutely insane.

Although the third-person shooter has been popular for months, Fortnite recently received a co-sign from Drake, which almost guarantees a product's stock will go up. Drizzy hopped online with world-renowned pro-gamer Ninja last week to live stream the game, earning Twitch their highest amount of concurrent viewers ever with 635,000 watchers. Now, the Epic Games installment can notch another tally mark in their "win" column.

According to a report by Sensor Tower, Fortnite has grossed more than $1.5 million worldwide in just four days from the Apple App store. The mobile version of the game hasn't been available for long, and it's still on an invite-only status. That means the game has yet to be released to the masses, and yet it is still raking in substantial amounts of revenue. Fortnite mobile was able to accumulate $1 million from in-game purchases alone within the first three days of launch. The game has also topped the iPhone download charts in over 40 countries, hitting that mark in 13 countries within the first 12 hours of release.

The closest mobile game competitors, Knives Out and Rules of Survival, made three times less in the same period of time.