Google enabled alphanumeric vanity numbers for click-to-call phone extension ad formats. "Vanity numbers allow businesses to include letters in their phone numbers. Including a vanity number with mobile ad can help users remember how to contact you. This's especially useful if most of your transactions take place over the phone and you want to customers to easily recall your phone.
In addition, featuring business name in phone number can be an effective method of driving brand recognition and ad performance," explained Google.
For e.g., instead of using 1-800-836-3464 in their mobile ad, 1-800-VENDING can use their actual business name.
To enable this feature, just enter the desired vanity number in the phone extensions field in your AdWords campaign setting. You must be based in the US and have your campaigns opted into showing on high end mobile devices with full Internet browsers.