The name of the numbers in English begins with one of these 13 letters : O,T,F,S,E,N,H,M,B,Q,U,D or G
So, the smallest numbers that start with different N letters in English are :

1                         1 One
2                       21 Twenty One
3                     102 One Hundred Two
4                     124 One Hundred Twenty Four
5                  1.146 One Thousand one Hundred Forty Six
6                  1.468 One Thousand Four Hundred Sixty Eight
7                41.689 Forty One Thousands Six Hundred Eighty Nine
8           1.004.689 One Million Four Thousands Six Hundred Eighty Nine
9    1.002.040.689 One Billion Two Millions Forty thousands Six Hundred Eighty Nine
10                          One Quadrillion one Billion Two Millions Forty thousands Six Hundred Eighty Nine
11                          One Undecillion one Quadrillion one Billion Two Millions Forty thousands Six Hundred Eighty Nine
12                          One Duodecillion one Undecillion one Quadrillion one Billion Two Millions Forty Thousands Six Hundred Eighty Nine
13                          One Googol one Duodecillion one Undecillion one Quadrillion one Billion Two Millions Forty Thousands Six Hundred Eighty Nine