True.

You'd only need my algorithm if you wanted to express the integer in a base other than 16 (or 8).

use bigint; 

my @digits=map chr,(0x30..0x39,0x41..0x5d);
my $base = 22;
my $n = 123456789123456;
my $h;
while($n > 0){
    $h .= $digits[ $n % $base ];
    $n /= $base;
}
print scalar reverse $h';
[download]

Result is 4E5G93GHBE8.