How to convert integers to characters in PHP

Question

How to create a function for converting integers to characters in PHP like this:

'A' => 0,
'B' => 1,
'C' => 2,
'D' => 3,
'E' => 4,
'F' => 5,
'G' => 6,
'H' => 7,
'I' => 8,
'J' => 9

If number is 100, then it should generate BAA.

The A, B, C... are just an example. I am trying to encrypt the numbers with a code.

I need this to work with some word like

0 => zero
1 => one

etc

But when I give number 10, it should output onezero.

Answer 1

Simple try like this

    $letter = chr($i+65);
    echo $letter;

gives 'A'