How much is 6 million million?

Six trillion, under the current international standard (formerly the "short scale"). The "long scale" used by the UK through the early 20th century separated -ion names for numerals by a factor of a million (1,000,000), with thousands of each unit designated by -iard names, i.e. * 1,000 thousand = 1 million * 1,000 million = 1 milliard * 1,000 milliard (1 million million) = 1 billion (10^12) * 1,000 billion = 1 billiard * 1,000 billiard (1 million billion) = 1 trillion (10^18) The "short scale" adopted by the US (and later the world) separated -ion names by a factor of a thousand. * 1,000 thousand = 1 million (10^6) * 1,000 million = 1 billion (10^9) * 1,000 billion = 1 trillion (10^12) * 1,000 trillion = 1 quadrillion (10^15)