Multiple choice The HCF of two numbers 2040 and 391 is: 17 21 16 18 Reveal answer Fill a bubble to check yourself A Correct answer Explanation Finding HCF of 2040 and 391. 391 = 17 × 23 (since 391/17 = 23). Checking if 17 divides 2040: 2040/17 = 120, which is an integer. Checking if 23 divides 2040: 2040/23 = 88.7, not an integer. Therefore HCF = 17.