According to the Census Bureau, the U.S. population exceeded 300,000,000 people at about 5:00 this morning (Pacific Time). You can see a current estimated population count here.
To make our national debt go away, each and every one of these people would need to pay in to the Treasury the equivalent of the MSRP of a 2007 Pontiac Grand Prix, about $28,500 each. Nice car. Too bad you don't get to drive it.
Some national debt is probably useful as a control on the cost of money and inflation. Some borrowing is necessary to keep the government afloat. But we've taken it way too far. The debt is only increasing, and soon we'll all have to buy Mercedes instead of Pontiacs.