Factorizer is a Windows program to find factors of numbers up to 2147483646 and to find primes pairs of primes and Palmen colors of numbers. Or in more detail Factorizer may be used: (1) to get the prime decomposition of all numbers in a range of numbers (2) to get all factors of a single number or all factors of all numbers in a range (3) to find only the prime numbers in a range of numbers (4) to find pairs of prime numbers (e.g. 107 and 109) in a certain range (5) to count (without displaying) the prime numbers in a range of numbers (6) to find Fermat and Mersenne primes less than 2147483647 and (7) to find the Palmen color of a number or the colors of a range of numbers. In addition a "filter" condition may be set to allow examination of numbers with a constant offset from an arithmetical or a geometrical progression e.g. just those numbers of the form 7*n - 12 or 10n + 2.