$bytes could theoretically be what you want, however it doesnt treat K as 1000, but as 1024 :S similarly, 1G = 1024K etc. it even adds commas, but at the same time doesnt handle really long numbers ;P

this code isnt too tested, but i tried to make it support extremely large input, so i had to pretty much remake /inc

alias hi! {
if ($2) {
var %n = $replace($2,T,12,G,9,M,6,K,3)),%x = $iif($left($1,- $+ %n),$v1,0),%r = $right($1,%n)
if ($mid($1,- $+ %n,1) > 4) %x = $regsubex(%x,/([^9]?)(9*?)$/,$calc(1+ \1) $+ $str(0,$len(\2)))
}
return $regsubex($iif($2,%x,$1),/(^\d+?(?=(?:\d{3})+(?:\.|$))|\G\d{3}(?=\d))/g,\t $+ $chr(44)) $+ $2
}

$hi!(3409734037340734,K) = 3,409,734,037,341K

$hi!(number) just adds commas, $hi!(number,bla) will divide like you asked.. bla can be T for 10^12, G for 10^9, M for 10^6 and K for 10^3. you can even add to them quite simply