My parents have an indoor planter and they have a lot of these worms in it. Anyone know what they are and if we should/need to get rid of them and how?

Thanks,
6t6

Roly poly?

looks like a millipede. Never had them but I'd try plunging the pots completely under water and leave them there for an hour or so. If they return clean all the dirt off roots and repot with fresh. I don't like to use chemicals.

Taking everything out is not an option, as this is a "built in planter" that is 2 ft x 12 ft.

I don't think it is what we would call a rolly Polly (or pill bug to us), but maybe?

Rake it all down about 2" to remove litter. Sprinkle diatomaceous earth over surface and add more soil with more de mixed into it.
If that does not work try spraying and watering in neem oil. If those are millipedes as I think they live in decaying vegetation. Better sanitation may solve the problem.