Based on the Biblical calendar, we know that the flood occurred in the year 4990 BC which was 6,023 years from creation (creation took place 11,013 BC - 4990 BC = 6,023 years).
We also know that the number 23 is used in the Bible to represent tribulation that comes in advance of, and accompanying God's judgment. For example, from the same flood date of 4990 BC until the cross of Christ in 33 AD is a span of 5,023 calendar years. Again, we see the fullness of a number in thousands is reached, and an attached modifying number (23) which represents tribulation. These Biblical dates are one reason that the year 2033 is so extremely important as much Biblical evidence indicates that it could be the last year of this world's existence: 4990 BC + 2033 AD = 7,023 calendar years (and of course, 2033 is also exactly 2,000 years since the cross of Christ and the time of His resurrection).
There is an interesting historical parable in the book of Joshua (chapter 6) wherein God commands the Israelites and Joshua to march around the city Jericho. First, they are to march around the city once a day for six days. Then, on the 7th day they are to march around 7 times and then after the 7th time around the wall of the city falls down flat and the army of Israel easily enters the city and slays all people except for Rahab and her family that were in her house which was protected by the scarlet thread (picturing the blood of Christ). This destruction really pictures the end of time when God will destroy all the wicked (those outside of the house protected by the blood of Christ) and save all of His elect people (those inside the house protected by the blood of Christ). Significantly, the wall falls down after the 13th time compassing the city. Remember the flood occurred 6,023 years from creation.
Then, if we start counting again and go 7,023 calendar years we arrive at the year 2033 AD.
Totaling 13,046 calendar years (13,045 actual years since there's no year zero). Or, we see the reason why God had the army of Israel change the routine after marching around once a day for 6 days (pointing the first earth that was destroyed in the days of Noah) and then march around 7 times on the 7th day-pointing to the next span of years (7,023) until there is total destruction of our present earth.