21 (alƙalami)

← 20 21 22 →
← 20 21 22 23 24 25 26 27 28 29 → ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	ashirin-ɗaya
Factorization (en)	3 × 7
Greek numeral	ΚΑ´
Roman numeral	XXI
Binary	101012
Ternary	2103
Octal (en)	258
Duodecimal (en)	1912
Hexadecimal (en)	1516

21

21 (ashirin da ɗaya) alƙalami ne, tsakanin 20 da 22.