Please explain how you can tell it is coming from outside US. Really would like to know rather taking calls at face value. I would probably not answer but would love to know how I can be even more sure.
The 407 area code with a 136 prefix is not a valid number for the United States. You can find that information from various websites when doing an Internet search. The caller ID is not displaying the country code before the number so people will answer the call thinking it's valid.