How this prime factors calculator works
Enter a whole number greater than 1. The calculator repeatedly divides that number by the smallest integer that goes evenly into the remaining value, starting at 2, and collects every successful divisor. Those divisors are the prime factors. For 12 the list is 2 × 2 × 3, because 12 ÷ 2 = 6, 6 ÷ 2 = 3, and 3 is prime.
Prime factorization writes a number as a product of primes only. 60 becomes 2 × 2 × 3 × 5. 100 becomes 2 × 2 × 5 × 5. 8 becomes 2 × 2 × 2. Repeated primes appear once for each time they divide. Multiplying every term recovers the original integer.
A prime number has only itself in the list. 7 shows 7. 97 shows 97. The smallest accepted input is 2, which also shows 2. Values of 1, 0, negatives, decimals, or an empty field are rejected with “Enter an integer greater than 1.”
This is not a full factor list. Factors of 12 include 1, 2, 3, 4, 6, and 12. This page shows only the primes that multiply to the number, joined with ×, in the order trial division finds them.