A double metric "kilo" prefix like that feels awkward. I know it's common, but I've always felt that we should just say "megameter" instead. (Also, a metric ton should just be called a "megagram".)
Agreed with megameter, but disagree with tonne: the kilogram is the base unit that physical constants etc. are measured against (e.g. Newton's constant is measured in Newton meter squareds per kilogram squared). It can be less confusing to talk about microkilograms than grams when doing physics.