Divine Might deals divine damage, and is multiplied on critical hits.
The damage from this feat is applied to the character, which means damage resistance does not apply.
This feat cannot be selected unless the character is leveling up as a class that has Turn Undead as a class feature. For example a multiclass Spirit Shaman and Cleric will not have the feat will available when leveling as a Spirit Shaman, even if all the prerequisites are met. Plan the level upgrade sequences accordingly.