There used to be a borax based powder you could find in hardware stores. I'm pretty sure it was called Roach Proof or something similar. It kills lots of different bugs though and you can get it down into the cracks.

there must be a repellent / killer you could use

I had to get Orkin, sadly, but when I came in the bathroom at 3am & a Huge one was on the toilet seat, that was It for me....
My Orkin guy tells me they live in leaf litter outside, come in for water.....

Well, personally I'd burn the house to the ground and then drop several nuclear bombs on it to make sure nothing at all could live there forever before I moved to a different country - or ideally, planet - where there are no centipedes.

I really don't like centipedes.

Move to a higher floor! That's my only answer. I live on the 2nd floor and never see centipedes in my apartment, but I sure did when I lived on ground floor and the basement... Can not kill the buggers, no matter how hard to smack em with a slipper, they keep wiggling, even when they're cut in half.