It makes calls! Just kidding. Well, half kidding. The phone is probably the least-used app on our home screen. But there’s a whole other mess of cool productivity tricks that Apple’s developers have built into the iPhone. For a roundup of the more common keyboard shortcuts and scrolling tricks, like how to take a picture of the screen or drop a pin in maps, check out Apple’s iPhone Tips page.

But the tricks go ever deeper. Here are a few advanced user tips we’ve found around the web. Did you know your iPhone could…

Turn Itself Off with a Sleep Timer?
Click through the Clock App and into the Timer tab. Set the timer for how long you want your iPhone to stay awake, then select “Sleep iPod” under “When Timer Ends.” It’ll shut off any open music or video apps, including Pandora.

Make International Calls Easy?
Instead of dialing the country exit code before each international call (That’s “011″ for everyone in the U.S. and Canada), just dial “+.” It’ll automatically pop up when you hold down the zero (“0″) key. So to call England, you’d dial +44 before the local area code and phone number.

Become a Scientific Calculator?
While inside the Calculator App, tilt your iPhone to landscape mode. You’ll be presented with a functional scientific calculator, featuring buttons for squares and square roots; sin, cos and tan; and factorials.

Easily Zoom Out on Maps?
You know you can use one finger to double-tap and zoom in on a map in the Maps App. But if you need to zoom back out, you can do it easily by tapping the screen with two fingers at once. It’s way easier than the pinch zoom method if you’re holding the phone in one hand or reaching across the car dashboard.

Set Custom Volume Profiles?
If you’re sharing your iPhone with, say, a teenaged fan of loud music, you can set custom volume profiles by switching out headphones. The headphone jack on your iPhone registers each individual set of headphones you plug in. The volume you set for each set of headphones will stay consistent each time you plug them in.

By Taryn Fiol