1000万亿的英语怎么说

"1000万亿"的英语是 "quadrillion".
"Quadrillion" 来源于拉丁语 "quadri-" 和 "illion", "quadri-" 意思是 "four", "illion" 意思是 "a very large number". 所以 "quadrillion" 的意思是 "a very large number with four groups of three zeros".
例句1:
The national debt has reached a quadrillion dollars.
翻译：国债已经达到了一万亿亿美元。
例句2:
The number of stars in the galaxy is estimated to be in the quadrillions.
翻译：银河系中的星星数量估计在数万亿亿。