Assuming you're talking about how difficult it is to span my fingers that long, it isn't really that hard. I felt a sort of strain when I tried to go to the 14th white key, but I had less strain when I just moved my thumb to the black key, probably because it was a little closer to the 13th white key than the 14th white key. So I rounded it to 14, because I included all the black keys and though I'd include that one too
(I hope that's what you were asking and I don't just sound like a noon because I didn't understand the question x3)
So, this is an octave.The distance between any two notes of that distance is an octave (and there are 13 total notes in an octave)
This is also an octave.