C 13b9, 4th inversion (Db in the bass)
Also written as C13b9/Db.
Notes, from the bass up
Db (bass)ACEGBb
The same notes as C 13b9 (Db, A, C, E, G and Bb), rearranged so Db is the lowest note. Use it to move between chords with smaller jumps across the keyboard.