Is it legal to sell a car with a broken odometer?

I purchased a car less than a week ago and of course we are noticing many problems we didn't when we first test drove the car. One major issue we are running in to is that all of the sensors seem to work intermittently including speedometer and odometer. After the fact I read that many of this make, model, and year have these kind of sparatic issues. My biggest concern being we have no idea what the actual mileage is on this car. Was it legal for this car to be sold to us in the first place considering the mileage given is most certainly false?