Ab 13#11, 4th inversion (A# in the bass)
Also written as Ab13#11/A#.
Notes, from the bass up
A# (bass)DE#G#B#D#F#
The same notes as Ab 13#11 (A#, D, E#, G#, B#, D# and F#), rearranged so A# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.