21021+5640
- Unique Name: 21021+5640STF2751
- RA: 21 02 09.00
- Dec: +56 40 11.1
- Discoverer: STF
- Discoverer Number: 2751
- Components:
- First year: 1828
- Last year: 2013
- Observations: 168
- First position angle: 343
- Last position angle: 357
- First separation: 1.5
- Last separation: 1.6
- Mag first component: 6.23
- Mag second component: 6.89
- Spectral type: B8III
- Primary proper motion RA: 5
- Primary proper motion DEC: 4
- Secondary proper motion RA: 5
- Secondary proper motion DEC: 4
- Durchmusterung: +56 2524
- Notes: D
