BigInteger

BigInteger is a Java class that is used to work with arbitrary length integer numbers. Python has a built in long datatype, which does the same, but works much easier because it can be used in expressions just like regular numbers. This is not possible in Java. Python even uses a long automatically if the result of an integer calculation exceeds the maximum machine size of the int type:

>>> a=12*12 
>>> print type(a),a 
<type 'int'> 144 
>>> a=12**12 
>>> print type(a),a 
<type 'long'> 8916100448256