Telephone number mappingUS phone numbers must be either 10 or 11 digits. A 11 digit number must start with a "1". The remaining 10 digits cannot start with a "0" or "1”Phone Number NotionTelephone number mapping Getting a vanity phone number with 4 repeating digitsI find that it's pretty useful to have access to multiple phone numbers. Any time a site offers a discount if you give them their phone number, or when you want to be more anonymous online and a service needs a number, it's nice to have a number that's more than a burner but not your main number.https://blog.jonlu.ca/posts/verizon-rare-numbers?ref=ls