What is 1 trillion x 1 trillion?

1 trillion x 1 trillion is equal to 1 quadrillion. To calculate this, you multiply the two numbers together: 1,000,000,000,000 x 1,000,000,000,000 = 1,000,000,000,000,000,000, which is 1 quadrillion. In scientific notation, this would be written as 1 x 10^15.