21510+5621
- Unique Name: 21510+5621KR 55AB
- RA: 21 51 00.59
- Dec: +56 21 19.3
- Discoverer: KR
- Discoverer Number: 55
- Components: AB
- First year: 1890
- Last year: 2011
- Observations: 20
- First position angle: 356
- Last position angle: 355
- First separation: 4.8
- Last separation: 4.6
- Mag first component: 10.31
- Mag second component: 10.69
- Spectral type: G5
- Primary proper motion RA: -8
- Primary proper motion DEC: -14
- Secondary proper motion RA: -2
- Secondary proper motion DEC: 7
- Durchmusterung: +55 2636
- Notes: D
