The former U.S. comptroller general and head of the Government Accountability Office (GAO) says the U.S. national debt is actually $65 trillion, more than three times the $18.5 trillion debt number generally cited.

Dave Walker, who headed the GAO under Presidents Bill Clinton and George W. Bush, said that the nation's vast unfunded liabilities are often left out of the picture when calculating the national debt, reports The Hill.

"If you end up adding to that $18.5 trillion the unfunded civilian and military pensions and retiree healthcare, the additional underfunding for Social Security, the additional underfunding for Medicare, various commitments and contingencies that the federal government has, the real number is about $65 trillion rather than $18 trillion, and it's growing automatically absent reforms," Walker told radio host John Catsimatidis of AM-970 in New York in an interview that aired Sunday.

Walker warned that continuing to allow the national debt to increase will hamper the government's ability to conduct domestic and foreign policy initiatives.

"If you don't keep your economy strong, and that means to be able to generate more jobs and opportunities, you're not going to be strong internationally with regard to foreign policy, you're not going to be able to invest what you need to invest in national defense and homeland security, and ultimately you're not going to be able to provide the kind of social safety net that we need in this country," he said.

He added that Americans have "lost touch with reality" when it comes to the incomprehensibly large debt.

Other analysts who have attempted to calculate the true national debt include Boston University Economics Professor Laurence Kotlikoff, who put the number at a staggering $210 trillion in 2014, or about $1,720,000 per taxpayer, more than 16 times larger than the debt estimated by the Congressional Budget Office, according to Brookings.

Paul Sheldon Foote, economist and professor at California State University, Fullerton, told Press TV on Sunday that the U.S. won't be able to pay off the national debt until it stops engaging in perpetual war around the globe.

"The deep hole we have for ourselves is much worse than politicians want to talk about, so they keep kicking the can down the road, hoping that somehow it will go away, but it cannot go away without economic growth and that cannot happen until we stop the endless wars and stop the endless programs for we promise people something for nothing," Foote said.