Piologie is a mathematical library to calculate with numbers of arbitrary precision. More details are available in the documentation (in German only). This iPhone App uses this library to provide the functions to factor large numbers and to calculate several thousand digits of mathematical constants.
Limitation of this version 1.0:
The computation of constant numbers is limited to 5,000,000 digits. But this high precision might not work for all constant numbers on all devices. The application aborts if not enough memory is available which might happen only for computations with more than 1,000,000 digits and complex computations (e.g. Euler-Mascheroni constant).
The factorization is based on different algorithms and has a checkpoint (after about 2 minutes) asking to continue with brute force which is only relevant for large numbers.