e164Number property

The phone number, represented as a leading plus sign ('+'), followed by a phone number that uses a relaxed ITU E.164 format consisting of the country calling code (1 to 3 digits) and the subscriber number, with no additional spaces or formatting, e.g.:

• correct: "+15552220123"
• incorrect: "+1 (555) 222-01234 x123".

The ITU E.164 format limits the latter to 12 digits, but in practice not all countries respect that, so we relax that restriction here. National-only numbers are not allowed.

References:

• https://www.itu.int/rec/T-REC-E.164-201011-I
• https://en.wikipedia.org/wiki/E.164.
• https://en.wikipedia.org/wiki/List_of_country_calling_codes