interval
A♯ major seventh
A♯lowerG𝄪upperM711 half steps
Eleven half steps: a half step short of the octave, which is why it leans on it.
On the keyboard
What is true of it
A♯ up a major seventh is G𝄪: 11 half steps, and 7 letters counting both ends.
Turn it upside down — put the A♯ on top — and it becomes a minor second. The two numbers always add to nine, and the two sizes to twelve.
It is a dissonance.
Every interval on A♯
A♯ → Bminor second · dissonanceA♯ → B♯major second · dissonanceA♯ → C♯minor third · imperfect consonanceA♯ → C𝄪major third · imperfect consonanceA♯ → D♯perfect fourth · perfect consonanceA♯ → D𝄪augmented fourth · dissonanceA♯ → Ediminished fifth · dissonanceA♯ → E♯perfect fifth · perfect consonanceA♯ → F♯minor sixth · imperfect consonanceA♯ → F𝄪major sixth · imperfect consonanceA♯ → G♯minor seventh · dissonance