In davening for Shabbos we say "Ki Shayshes Yamim Asah Hashem Es Hashamayim V'Aretz", for in six days Hashem created the Heavens and Earth.

The Medrash on the word "Berashis" tells us that is means "Bishveal Yisrael Sh'karah Rayshis", the world was created for Yisrael, who is called Rayshis - beginning. The Medrash also tells us "Histakel B'Oraysa U'Barah Olamah", Hashem looked in the Torah and created the world.

From this we see that Yisrael and the Torah are very similar. In fact Chazal tell us "Yisrael V'Oraysa Chad Hu" - Yisrael and the Torah are one. One of the things that they have in common is the number 600,000. There are 600,000 souls in Klal Yisrael and 600,000 letters in the Torah. (As a matter of interest the word Yisrael makes up the Pasuk "Yesh Shivim Rebu Osiyos LaTorah", which means there are 600,000 letters in the Torah.)

This leads us back to Shayshes Yamim - 6 days. The word Shayshes is made up of the letters Shin, Shin, Tuf and has a gematria of 1,000. If we multiply it by the number of the word itself - 6 - we get 6,000. The word Yamim is made up of the letters Yud, Mem, Yud, Mem and has a gematria of 100. If we multiply the 6,000 of Shayshes by the 100 of Yamim we get a total of 600,000. This tells us that Hashem created the world in 600,000 - both the Torah and Yisrael together are the foundations of Creation and the world in which we live.