To add to the answer from RGTuffin, you most propably also need to know the minimum lengths for a phone number. Consider following number:
1441232
If searching for bermuda (1441) this matches, so the result could be that you interpret this as a phone number from bermuda. This would result that the phone number is 232, but it's most certainly not true. Then again if you take out the prefix for U.S. (1) the phone number would be 441232.
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