piano chord
A♯m7
A♯1C♯♭3E♯5G♯♭7
Minor triad with a minor seventh. The same four notes as a major sixth chord a third above.
Written the other way round it is B♭m7 — the same twelve keys on a piano, a different piece of notation.
What is true of it
A♯m7 is A♯, C♯, E♯ and G♯ — 1, b3, 5 and b7 counted from A♯.
These are also the notes of C♯6/A♯ and D♭6/A♯. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
On an instrument that cannot reach all 4, the 5 goes first, in that order.