600,000

In this week's Perasha, the Jewish people were counted to have 603,550 men from age 20-60 besides the tribe of Levi.  There were about 600,000 souls when they left Egypt, says the Torah in Parshat Bo.

Any other significance to the number 600,000?

The Hebrew-language Wikipedia article on it gives us some more examples:

• Many opinions hold that a public domain (Reshut Harabim) must have at least 600,000 people passing through it each day
• One who sees 600,000 Jews together says the blessing חכם הרזים.
• The gemara in Gittin that talks about the 600,000 cities on Tur Malka
• The Zohar says that there are 600,000 letters in the Torah.  This isn't true - it's closer to 305,000 - but there are many explanations to explain this concept.
• It's brought down in writings of Hasidut that there are 600,000 souls of Israel.
• The Kol Hator said, "If it would be possible to bring 600,000 [Jews] to Israel at one time, one should do so immediately because this number of 600,000 has a great and complete power to overpower the Samech Mem in the gates of Yerushalayim."
• Rav Akiva Yosef Shlezinger writes in "Berit Olam" that if there will be 600,000 Jews in Israel, the nations will give the Jews permission to rule in the land.  Some tie these words to the fact that at the time of the War of Independence (in 1948), 600,000 Jews lived in the Yishuv of Israel.  Also, during the Six Day War, the IDF had approximately 600,000 soldiers, which is something that hints to the redemption of these events.

Ribbi Yaakov Abuhatzeira asks in Mahsof Halavan why HKB"H needed to count the Jewish people in this week's Perasha.  He explains that the Jewish people could not have any less than 600,000 when they left Egypt.  The reason is because the Torah has 600,000 letters and 600,000 explanations so there needed to be 600,000 souls so that each soul could take one letter and one explanation.  All three of these (letters, explanations, and souls) are hinted to in the following acronyms for ישראל (Yisrael):

יש ששים רבוא אותיות לתורה

יש ששים רבוא אופנים לתורה

  יש ששים רבוא אורות לישראל

The main count in this week's Perasha, therefore, is to show the Jewish people that they should not be weak in their Torah study.  Hashem is telling them that they will never be less than 600,000 souls since the Torah has 600,000 letters and explanations, and that they need to busy themselves with Torah study day and night so that the lights of the Torah and the lights of their souls will shine.  If some individuals are lax in their Torah study, the collective will be missing part of the complete Torah.  In addition, this laxity of Torah study causes a plague to come during the count, which is why a Kofer Nefesh is required during the count to prevent a plague, as the Torah states elsewhere.  See the Mahsof Halavan inside.

The current Jewish population of Israel is 5,837,000.  Here's a blog that says that it will reach 6,000,000 by next Yom Ha'atzma'ut.  Besides reaching the number of souls of the Holocaust, there's another interesting stat here.

Based on 2009 numbers, 25.2% of the Jewish population is a male from 20-60.  This would make the total Jewish males from 20-60 this year equal approximately 1,471,040. 

Wikipedia states:

According to a 2004 Israel Central Bureau of Statistics study[citation needed] on Israelis aged over 18, 8% of Israeli Jews define themselves as haredim (or Ultra-Orthodox); an additional 9% are "religious" (predominantly orthodox, also known in Israel as: Zionist-religious, national-religious and kippot srugot); 12% consider themselves "religious-traditionalists" (mostly adhering to Jewish Halakha); 27% are "non-religious traditionalists" (only partly respecting the Jewish Halakha), and 43% are "secular". Among the seculars, 53% say they believe in God. Due to the higher natality rate of religious and traditionalists over seculars, the share of religious and traditionalists among the overall population is even higher.

Let's say the hareidim and Zionist-religious all study Torah - if not all day, periodically.  I would say that the "religious-traditionalists" have also studied Torah periodically in a Torah class here and there.  That gives us a population of 426,602.  Add to that a good percentage of the "non-religious traditionalists" plus all the students studying from abroad who are over 20 and learning Torah in Israel, plus the fact that these percentages are from 2004 and they're growing, I'm sure we will soon have 600,000, if not already.

The physical battles (in 1948 and 1967) required the physical 600,000.  The spiritual battles require the spiritual 600,000.  In Egypt, we had much more than 600,000 who died in the plague of darkness because they weren't ready spiritually.  When the time of the redemption came, only 600,000 remained.  Those who remained were worthy of redemption because they were going to receive the Torah 50 days later.  May we continue to grow and go מחיל אל חיל and be worthy of our own Final Redemption - may it come בב"א.