Digit, or character?

What alphabet?

0,1,2,3,4,5,6,7,8 or 9 ??

I have this feeling you're going say "8", because on its side it's the symbol for infinity... :-)

which base?

en base 10

me entro la duda ... me parece que es : 9 elevado a 9 elevado a 9 seria algo asi como 9 al exponente 387420489