+23247 The first prime is 2: 420 ÷ 2 = 210
210 is also divisible by 2: 210 ÷ 2 = 105
105 is not divisible by 2, so try the next prime number -- 3: 105 ÷ 3 = 35
35 is not divisible by 3, so try the next prime number -- 5: 35 ÷ 5 = 7
7 is a prime number, so the answer is: 2 x 2 x 3 x 5 x 7
+23247 The first prime is 2: 420 ÷ 2 = 210
210 is also divisible by 2: 210 ÷ 2 = 105
105 is not divisible by 2, so try the next prime number -- 3: 105 ÷ 3 = 35
35 is not divisible by 3, so try the next prime number -- 5: 35 ÷ 5 = 7
7 is a prime number, so the answer is: 2 x 2 x 3 x 5 x 7
