Some demographic considerations

When Jacob's household settled in Egypt, there were 70 members.
All the offspring of Jacob were seventy persons (Exodus 1:5a)
After 430 years, when the Israelites left Egypt, there were 600,000.
The time that the people of Israel dwelt in Egypt was four hundred and thirty years (Exodus 12:40).
And the people of Israel journeyed from Rameses to Succoth, about six hundred thousand men on foot, besides women and children (Exodus 12:37).
For a more detailed breakdown of this number, we may refer to Numbers 1:20-43.

Reuben	46500	Simeon	59300	Gad	45650	Judah	74600
Issachar	54400	Zebulun	57400	Ephraim	40500	Manasseh	32200
Benjamin	35400	Dan	62700	Asher	41500	Naphtali	53400

Here, the Levites were not counted. Joseph and Levi were replaced by the two sons born to Joseph in Egypt, Ephraim and Manasseh.
Was this figure an exaggeration? Not quite. Take a pen and calculate.
Let us assume that 30 years make up one generation. There were 14.33 generations in 430 years.
You may object to this number because Isaac was born to Abraham when he was 100 (Genesis 21:5) and Jacob was born to Isaac when he was 60 (Genesis 25:26). Since Abraham, Isaac and even Jacob were sojourners. Therefore, it took longer for them to get married and to bear children. But I believe that 30 was a reasonable number of years for settled people to give birth to the next generation.
Let us further assume that population growth follows an exponential rate, like that of compound interest.
So, let R be the rate of population growth. To find out the value of this rate, solve the following equation.

70 * R^14.33 = 603550

and we get R=1.88. That is to say, 30 years after arriving at Egypt, there were 132 Israelites. After 60 years, there were 247 and 90 years 465 etc. This rate looks reasonable. What about people who died? Don't worry, mortality has been taken care of in this equation. This growth rate is the difference between birth-rate and death-rate. Some died young, some died a full age of 180 (Genesis 35:28). The average is probably 120 (Genesis 6:3).

What about the next 40 years? This R would not apply to the Israelites in the wilderness. The mortality rate would be very much higher than the birth rate. Just imagine. How are you going to support an army of 600000 soldiers for 40 years in the desert? How do you maintain the food supply and water supply for so many people for so long in the wilderness?
Indeed, it would not have taken forty years to travel from Egypt to Canaan, if the Israelites had not worshipped the golden calf at the foot of Mount Sinai. I hold the view that God wanted to wipe out the generation of idol-worshippers in the wilderness, so that a new breed of uncontaminated Israelites might enter the Promised Land.
If the duration of one generation had extended from 30 to 40 years in the wilderness and the number of Israelites entering Canaan remained the same, i.e. 600000, it means 530000 (600000 * 0.88) Israelites had died in the wilderness within the 40 years, an average of 13200 per year or 22 per 1000 per year. Currently, some 3500 years later, according to an estimate in the CIA World Factbook, the crude death rate for the whole world in 8.23 per 1000 per year. Science and technology has made much progress in lengthening the life span and improving the quality of life of modern men.
Let us return to these half a million people. They deserved to die because they worshipped the golden calf. If you think God was cruel, killing some 50000 people in 4 years, think again how many Jews the Nazi had killed in 4 years. It was 6 millions. God was 120 times more merciful than the Nazi!

Dear Lord, numbers can be numbing. Let us appreciate the real significance of the truth beneath these numbers. Amen.