I have no personal experience but it can purify water, disinfect a wound and start a fire when combined with glucose, glycerine or antifreeze. It is an oxidizing agent.

here is something I found online;
Potassium permanganate is often included in survival kits along with either glycerine or a glucose tablet for the purposes of making fire. The glucose tablet can be ground up, mixed with the potassium permanganate and caused to combust by applying friction. It can also be mixed with anti-freeze from a vehicle to produce flame, although this can be dangerous and should be done in a controlled manner ie dipping some paper into the anti-freeze and then adding a small amount of potassium permanganate. The ability to sterilise water and wounds is also advantageous and another reason for inclusion in a survival kit.

High-grade potassium permanganate can be found at pool supply stores and is used in rural areas to remove iron and hydrogen sulfide (rotten egg smell) from well water.