SI Prefix (Système International d’Unités)

A name or associated symbol that precedes a unit of measure:

1024 yotta (Y)
1021 zetta (Z)
1018 exa (E)
1015 peta (P)
1012 tera (T)
109 giga (G)
106 mega (M)
103 kilo (k)
102 hecto (h)
101 deca (da)
10–1 deci (d)
10–2 centi(c)
10–3 milli (m)
10–6 micro (µ)
10–9 nano (n)
10–12 pico (p)
10–15 femto (f)
10–18 atto (a)
10–21 zepto (z)
10–24 yocto (y)

http://www.bipm.org/en/si/prefixes.html