Prime factorization calculator
(This uses Eratosthenes sieve up to a point and then works through brute force.
It allows both the run time of the creation of the sieve and of the prime factorization to be displayed.)
Numbers may be entered as integers or as arithmetic expressions like
2^31-7
2*3*5*7 - 1
3*(5+7)*11^2
Only one exponentiation (^) may be used and parentheses may not be parsed properly
Some nice primes
30029 = 2*3*5*7*11*13 - 1
3263443 = 2*3*7*43*13*139 + 1
901830931 = 2*3*5*7*11*13*59*509 + 1
32464862431 = 2*3*5*7*11*13*17*19*3347+1
317132017 = (2*3*5*7*11*13*17*19*23*317+1)/223
30635719141
314159 How many substrings of pi are prime?
157079632679 Half of pi
15485863 -- The one millionth prime