I wanted to say the same thing, but I'm late, I guess:

use bigint;

my $n = 123456789123456;
my ($h, $d);
while ($n > 0) {
    $d = $n % 16;
    $n /= 16;
    $h .= sprintf "%x",$d;
}
print scalar reverse $h;

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In reply to Re^2: long integer to hexadecimal conversion by kikuchiyo
in thread long integer to hexadecimal conversion by perl_fan

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