In addition to the relatively well-known "Gematria" (which has been the subject of several threads in HM), there is some number mysticism in Judaism which is little known to Gentiles.
Two samples: first certain numbers have various mystical significances. The Jewish Encyclopedia, article "Numbers and Numerals" (Volume IX pages 348-349) lists the following: 2, 3, 3 1/2, 4, 7, 10, 22 (the number of letters in the Hebrew alphabet), 40, 60, 70, and 60 myriads.
The Sefer Yetzirah (date unknown, probably between 3rd and 6th century of the common era) has an elaborate number mysticism. From the article "Yetzirah, Sefer" in the Jewish Encyclopedia (volume XII pages 602-606) we find: the are three "mother" letters, "mute mem" which also represents water in which the mute fish live, "hissing shin" which also is the hissing fire, and "airy aleph" which is the air. (Similar to the earth-air-water-fire system, except that earth does not appear. Does this sound anything like the salt-sulfur-mercury system?) The three seasons of the year (winter, summer, rainy) correspond with water, fire, and air.
Of the remaining letters, 7 are "doubles" and 12 are "singles". The 7 double letters produced the seven planets, the seven days of the week, and the 7 apertures of man (2 eyes, 2 ears, 2 nostrils, and 1 mouth). The twelve single letters produced the twelve signs of the Zodiac, the twelve months, and the 12 organs (hands, feet, kidneys, gall, intestines, stomach, liver, pancreas, and spleen) which are in turn subject to the twelve signs of the Zodiac. There is also some esoterica developed from the 231 combinations of the 12 letters taken 2 at a time.
I hope this gives some of the flaovr of Kaballistic number mysticism. Unfortunately beyond the Jewish Encyclopedia articles cited above, and a brief mention in Gerson Sholem's _Kabbalah_ (Jerusalem: Keter Publishing House, 1974, no ISBN, reprinted in the USA by New American Library), I do not have any sources, readable or otherwise, on Kaballistic numerology.