Il numero 21, ventuno in Italiano, in Inglese si dice twenty-one.
Il numero ordinale 21° in inglese si dice twenty-first.
12: twelve 13: thirteen 14: fourteen 15: fifteen 16: sixteen 17: seventeen 18: eighteen 19: nineteen 20: twenty 22: twenty-two 23: twenty-three 24: twenty-four 25: twenty-five 26: twenty-six 27: twenty-seven 28: twenty-eight 29: twenty-nine 30: thirty