Numerical Prefixes: Mathematical, Digital, IEC

These are the commonly used numerical prefixes in the English language, but most seem to translate with European languages.

 Mathematical Prefix Symbol Name Multiplier vendeko v decillionth 10-33 nonillionth 10-30 xenno x octillionth 10-27 yocto y septillionth 10-24 zepto z sextillionth 10-21 atto a quintillionth 10-18 femto f quadrillionth 10-15 pico p trillionth 10-12 nano n billionth 10-9 micro µ millionth 10-6 milli m thousandth 10-3 centi c hundredth 10-2 deci d tenth 10-1 deka da ten 101 hecto h hundred 102 kilo k thousand 103 mega M million 106 giga G billion† 109 tera T trillion† 1012 peta P quadrillion 1015 exa E quintillion 1018 zetta Z sextillion 1021 yotta Y septillion 1024 xenna X octillion 1027 V nonillion 1030 vendeka V decillion 1033 undecillion 1036 duodecillion 1039 tredecillion 1042 quattodecillion 1045 quindecillion 1048 sexdecillion 1051 septendecillion 1054 octodecillion 1057 novemdecillion 1060 vigindecillion 1063 googol 10100 googolplex 10google

 Digital (Base 2) Prefix Symbol Multiplier Value peta P 250 1,125,899,906,842,624 tera T 240 1,099,511,627,776 giga G 230 1,073,741,824 Mega M 220 1,048,576 kilo k 210 1,024

 IEC Version Prefix Symbol Multiplier Value exbi Ei 260 1,152,921,504,606,846,976 pebi Pi 250 1,125,899,906,842,624 tebi Ti 240 1,099,511,627,776 gibi Gi 230 1,073,741,824 mebi Mi 220 1,048,576 kibi Ki 210 1,024

 Non-Technical Writing Prefix Value uni,  mono 1 bi 2 tri 3 quadr 4 quint, penta 5 hex, sex 6 hept, sept 7 octo 8 novem 9 deca, deka 10

† 1,000,000,000 is called "one billion" in the U.S., U.K., France (before May 3, 1961), Brazil, Puerto Rico, Greece, and in Italy, Russia and Turkey it is referred to as "one billion" when written out, but as "one milliard" when written as 109. 1,000,000,000,000 is called "one trillion" in the U.S., but is called "one billion" in Germany, the Netherlands, Austria, Sweden, Norway, Denmark, Finland, France (after May 3, 1961), Portugal, Poland. It is best to check for current definitions for each country to be certain to get it right, or better yet, just write it out numerically to avoid confusion.

Thanks to Duncan for the zepto info.