The factors of 26 are one, two, 13 and 26. One and the number itself, in this case 26, are always factors. Since 26 is an even number, which means that it ends in zero, two, four, six or eight, it's evenly divisible by two. Two times 13 equals 26.
No numbers between two and 13 divide evenly into 26, so there are no more factors other than the four listed. Because two and 13 are both prime numbers, which are numbers that are only divisible by one and themselves, the prime factorization of 26 is 2 x 13. The prime factorization of a number refers to the prime numbers that multiply together to make that given number.