This isn't directly mentioned on the wiki page, but I had a hunch and after experimenting I found out that iprange will read numeric notation directly! So something like:
iprange 18279424 -> 1.22.236.0
iprange 18279424/24 -> 1.22.236.0/24
iprange 18279424-18279679 -> 1.22.236.0/24
Pretty nifty! That's less conversion back & forth when storing IPs in numeric / integer form.