Kaph = 20, ordinal 11, reduced 2, final form ך = 500. Spelled in full, כף = 20+80 = 100.
Meaning
Kaph is 'palm' or the hollow of the hand, one of the seven doubles (k/kh), and the letter of the hand that receives and gives. Its 20 is its value as the first of the tens after yod, and its final form 500 is the first of the five hundreds — kaph is where the numeral system turns from the alphabet's 400 into the finals' 500.