I checked a couple but none were found if I included the area code.

Based on my sample size of half a dozen phone numbers, it doesnt seem to have numbers once they are more than 8 digits.

Seems like there should some formula to determine how long the normal number needs to be to have all digits go to a certain length.

Reminds me of the formula for calculating the shortest path to watch all episodes in a tv series in all possible orders.