mobile calls

I missed a call on my mobile and when I looked at the number it was 12 digits long(074*********). I thought all mobile numbers were 11 digitsI did not call it back because I have the attitude if its important they will leave a message or phone again.Also it could have been a scam number which fed a premium line

Peter I always put the number in the search bar & it says "Who called me" if it's a scam it'll tell you