The genome of the cockroach was recently sequenced, and scientists have gained some insight into why they are so tough. They can survive in an incredible array of environments, they are great at reproducing, they can get over severe wounds, and as it turns out, they are also evolving. Some roaches now know to avoid certain insecticides.
In an incredible feat of self-preservation, they can also reproduce asexually. The video explains it in more detail, but females can lay eggs that will hatch, all without the help of a male.
So why research the cockroach genome? Scientists are already putting some of this data to use. A drug that was inspired by the regenerative abilities of the roach is in development; it aims to speed wound healing.