In words	Prefix (Symbol)	Decimal	Power of ten	Order of magnitude
nonillionth	quecto- (q)	0.000000000000000000000000000001	10−30	−30
octillionth	ronto- (r)	0.000000000000000000000000001	10−27	−27
septillionth	yocto- (y)	0.000000000000000000000001	10−24	−24
sextillionth	zepto- (z)	0.000000000000000000001	10−21	−21
quintillionth	atto- (a)	0.000000000000000001	10−18	−18
quadrillionth	femto- (f)	0.000000000000001	10−15	−15
trillionth	pico- (p)	0.000000000001	10−12	−12
billionth	nano- (n)	0.000000001	10−9	−9
millionth	micro- (µ)	0.000001	10−6	−6
thousandth	milli- (m)	0.001	10−3	−3
hundredth	centi- (c)	0.01	10−2	−2
tenth	deci- (d)	0.1	10−1	−1
one		1	100	0
ten	deca- (da)	10	101	1
hundred	hecto- (h)	100	102	2
thousand	kilo- (k)	1000	103	3
million	mega- (M)	1000000	106	6
billion	giga- (G)	1000000000	109	9
trillion	tera- (T)	1000000000000	1012	12
quadrillion	peta- (P)	1000000000000000	1015	15
quintillion	exa- (E)	1000000000000000000	1018	18
sextillion	zetta- (Z)	1000000000000000000000	1021	21
septillion	yotta- (Y)	1000000000000000000000000	1024	24
octillion	ronna- (R)	1000000000000000000000000000	1027	27
nonillion	quetta- (Q)	1000000000000000000000000000000	1030	30
In words	Prefix (Symbol)	Decimal	Power of ten	Order of magnitude