21700 may refer to:

• 21,700 (number)
• 21700 (year)

• 21700 Caseynicole (1999 RD₇₂), a Mars-crossing asteroid, the 21700th asteroid registered
• Jalapa, Baja California, Mexico (postal code: 21700)
• Lice, Turkey (postal code: 21700)
• La Palma del Condado (postal code: 21700), Huevla, Spain
• 21700. a postal code in Côte-d'Or, Bourgogne-Franche-Comté, France; used for several communes, see Communes of the Côte-d'Or department

• 21700 battery, a cylindrical battery cell form factor for rechargeable lithium-ion batteries
• U+2170x (Unicode character block), see List of CJK Unified Ideographs Extension B (Part 2 of 7)

• All pages with titles beginning with 21700
• All pages with titles containing 21700
• 2170 (disambiguation)
• 217 (number)
• 217 (ISO year +217; A.D. 217 / 217 CE)