Not sure what the number is for, I received a text from this number something about activating or download my app.   I have never gotten a app by text before with a telephone number before.  It seems strange.

have not reguested any apps dont know who this is

It's a notification from Facebook containing a link to Google Play, where you can download a specific game app to your cell. Someone may have entered their phone number incorrectly or pranked your number. No big deal.

How do you know this ?
Please provide a link that is on the Facebook website that explains that they use this number.