piano chord
A♯
A♯1C𝄪3E♯5
A major third and a perfect fifth over the root.
Written the other way round it is B♭ — the same twelve keys on a piano, a different piece of notation.
What is true of it
A♯ is A♯, C𝄪 and E♯ — 1, 3 and 5 counted from A♯.
C𝄪 is a double sharp, and it has to be: every letter from A♯ upwards is used once, so the 3 cannot be written any other way.
On an instrument that cannot reach all 3, the 5 goes first, in that order.