It doesn’t matter which currency you use, one quadrillion is a massive number. In Japan, it represents a milestone as the country tops one quadrillion in public debt for the first time. Yes, that’s 15 zeros: 1,000,000,000,000,000.

It’s not a number you see very often, but Japan also has more public debt than most advanced economies. Its total debt, 1.009 quadrillion is more than the economies of Germany, France, and the U.K. combined, or 240 percent of Japan’s GDP.

To comprehend the magnitude of the number in other ways, it would take 31 million years to count to one quadrillion and we only have 100 trillion cells in our body.

Japan is considering a sales tax to slow rising debt as the government has been borrowing money to jumpstart the economy. Still, even if the tax plan goes through, the government would have a deficit of two percent of the economy in 2020.

Comparing U.S. debt to Japan, if you convert U.S. debt (about $15 trillion) into Japanese yen, it too reaches the quadrillions (about 1.5 quadrillion), but the debt is also a much smaller percentage of U.S. GDP.

So what’s next? A quintillion? Hopefully not anytime soon.