Apple Inc. has recently come under attack for its practice of stockpiling cash. At the end of last year, the company was sitting on $137 billion —and the heap keeps growing.

Corporations normally don't hoard cash the way Apple does. They keep enough around for immediate needs, and either invest the rest in their operations or dole it out to shareholders in the form of dividends or stock buybacks. If they need more cash for, say, an acquisition, they borrow it.

Apple has never explained why it is salting away so much money —other than to say the company is preserving its options.

The money belongs to shareholders, so Apple is limited in what it can legally do with it. Leaving legality aside, here are some things Apple could do with $137 billion:

—Give every American a check for $437.

—Buy 213 million iPhones at the average wholesale price, enough for every American who lives east of the Mississippi River, plus Texas.

—Based on market value at Thursday's close, Apple could acquire Facebook, Groupon, LinkedIn, Netflix, Pandora, Research In Motion (Blackberry), Yahoo, Yelp, Zillow and Zynga —and have more than $2 billion left to spare.

—Create a stack of dollar bills 9,300 miles high, 38 times higher than the orbit of the International Space Station.

—Buy 100,000 luxury Manhattan apartments, enough to house the population of Omaha.

—Foot the bill for U.S. federal spending on education for two years.

—Give every Apple employee a bonus of $1.7 million.

—Double U.S. foreign economic aid to the developing world for three and half years.

—Provide shareholders with a one-time dividend of $145 per share. (The stock closed Thursday at $456.95)