I recall something about having to cut them in a certain spot but not wether both ends will survive. Also that they have male genitalia on one end and female on the other.
Just looking at an earthworm, you can see they are divided offcenter by that saddle thing mentioned previously. This in itself is asymetrical suggesting that cutting them in half will not work as only one half would have the saddle.

If a person thumps on the ground will it bring worms to the surface?

If an electric current is run through the ground like in the movie "Godzilla" with Mathew Broderik, will it bring them to the surface?

Do earthworms lay eggs?

What is the average life-span of an earthworm?

What is the average distance traveled by an earthworm in it's lifetime?

Do earthworms breathe air?

How and what do earthworms eat?