PHP, 27 (Cracked by bwoebiCracked by bwoebi)
Code:
$$((()))02679;;=__bdeehiinx
Output (default on PHP 5.4.x):
3.1415926535898
Output (default on PHP 5.5.x):
3.14159265359
Hint: It depends on your php.ini precision, so hopefully it's acceptable.
Original:
$_=hex2bin(7069);die($_());