The prefix mega means one million; this prefix means one billion
When you're going up to a larger prefix, from Kilo to Mega for 
example, the ... For example, 1 Kilobyte is often used to mean 1000 bytes (base 
10), or it can... [DOC] [TLE] Physics reference: SI prefixes - Alcyone Systems [PAR] tera, T, 1012, 1 000 000 000 000, U.S. trillion; U.K. billion.