Bb Major 7#11, 2nd inversion (E# in the bass)
Also written as Bbmaj7#11/E#.
Notes, from the bass up
E# (bass)AEA#D
The same notes as Bb Major 7#11 (E#, A, E, A# and D), rearranged so E# is the lowest note. Use it to move between chords with smaller jumps across the keyboard.