What is bigger than a Kilo meter?

Answer 1

1000km = 1 Megameter (Mm) a thousand km

1,000,000km = 1 Gigameter (Gm) a million km

1,000,000,000km = 1 Terameter (Tm) a billion km

and it goes on further Petameter, Exameter, Zettameter, Yottameter.

Answer 2

In theory you can use other SI prefixes with "meter", for example megameter, or gigameter. However, those aren't used in practice - rather, scientists tend to just use meters or kilometers - or, in the case of astronomy, the non-SI units "astronomical unit", "light-year", and "parsec".