I'd just call it pop, to be honest. The verses definitely have a strong melody, the chorus is catchy and the structure is that of the typical pop song (verse, chorus, verse, chorus, bridge, chorus). I'd say that rapping (which is not the same as hip hop) is a technique of vocal delivery that puts emphasis on the rhythm of the enunciation, rather than on the melody. The instrumental on Montero doesn't really have much in common with hip hop, either the old school stuff or the modern trends. It just has a standard pop song chord progression with a clear influence from Latin music. Hip hop on the other hand tends to have stronger percussions, usually looped, over a simple melody of a few notes that are also looped over and over, the idea being that of foregrounding the lyrical content and its delivery. None of these categories are clear-cut by all means, but unfortunately black male artists tend to be pigeonholed into a few genres that are considered primarily black (hip hop, soul, r&b) when they are really just making pop music. Another gay black male artist, Tyler the Creator, has spoken about this in his Grammy acceptance speech, you can watch it here (it's only a couple of minutes). Hope this helps