SI

SI Prefixes

Power	Symbol	Name	-illion
-30	$\mathrm{q}$	quecto	nonillionth
-27	$\mathrm{r}$	ronto	octillionth
-24	$\mathrm{y}$	yocto	septillionth
-21	$\mathrm{z}$	zepto	sextillionth
-18	$\mathrm{a}$	atto	quintillionth
-15	$\mathrm{f}$	femto	quadrillionth
-12	$\mathrm{p}$	pico	trillionth
-9	$\mathrm{q}$	nano	billionth
-6	$\mu$	micro	millionth
-3	$\mathrm{m}$	milli	thousandth
-2	$\mathrm{c}$	centi	hundredth
-1	$\mathrm{d}$	deci	tenth
1	$\mathrm{da}$	deca	ten
2	$\mathrm{h}$	hecto	hundred
3	$\mathrm{k}$	kilo	thousand
6	$\mathrm{M}$	mega	million
9	$\mathrm{G}$	giga	billion
12	$\mathrm{T}$	tera	trillion
15	$\mathrm{P}$	peta	quadrillion
18	$\mathrm{E}$	exa	quintillion
21	$\mathrm{Z}$	zetta	sextillion
24	$\mathrm{Y}$	yotta	septillion
27	$\mathrm{R}$	ronna	octillion
30	$\mathrm{Q}$	quetta	nonillion

Patterns

• Past $10^{\pm 6}$, -illion usage starts and the metric prefix names end all in either “o” or “a”
• Past $10^6$, capital letters are used for the metric prefix symbols
• Past $10^{\pm 21}$, opposing lower and upper case symbols are used (e.g. $10^{-21}$ is z while $10^{21}$ is Z)