Take a look at the numbers your last several (non-friend) texts have come from. A lot of the ones from businesses will show a 5- or 6-digit "short code," rather than a regular phone number.

Money expert Martin Lewis says mobile phone customers can save money by sending a text to a 5-digit number.

Company-sponsored text numbers are different. There’s no area code, no digit spacing. Will the scammers figure out how to make it look like a 4-digit number?