The gematria of Kaf is 20.

Twenty can be divided into ten and ten. The first ten represents the Ten Utterances with which G‑d created the world. The second ten represents the Ten Com­mandments. Together, they become a kaf. In Numbers it states: “Ten-ten is the kaf.”

If you take the word עשרים (esrim, the word “twenty” in Hebrew) and add up its letters, you arrive at 620: ayin=70, shin=300, reish=200, yud=10, mem=40. 620 is also the gematria of the word כתר, kesser: kaf=20, tav=400, reish=200. Kesser means crown, the ornament placed on the head of a king. Kesser also reminds us of the 620 letters in the Ten Command­ments. G‑d crowned the Jewish nation by giving them the Torah. And it became the Jews’ raison d’êtreto follow the 613 commandments and the 7 Rabbinic laws—which together total 620. Significantly, the first letter of kesser is kaf.