F# 13#11, 5th inversion (B# in the bass)
Also written as F#13#11/B#.
Notes, from the bass up
B# (bass)D#F#A#C#EG#
The same notes as F# 13#11 (B#, D#, F#, A#, C#, E and G#), rearranged so B# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.