What is significant about the number 400?

• 400 is 20²
• 400 is divisible by: 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 200, 400
• 400 equals 2⁴ * 5² or ( 2*2*2*2*5*5)
• 400 is a self-number which are generated by this formula:
• You can write 400 like this: four hundred, which is referred to as its Cardinal representation
• 400 comes after 399 and 401 follows 400
• 400² is 160000
• An HTTP Status code of 400 means, Bad Request, which could not be understood by the server due to a malformed syntax.
• 6 minutes and 40 seconds is equal to 400 seconds
• 400 is a Harshad number
• 400 can be represented in Greek by Υ´
• The scientific notation of 400 is 4 * 10²
• There was an Atari 400 computer, my first computer was an Atari 1200XL
• 400 in binary is 110010000
• 400 is represented in Roman number CD
• There are 400 days in a Gregorian calendar
• 400 in hexadecimal is 0x190
• The Sun is 400 times larger than the moon and 400 times further away from the Earth
• Counting to 400 will take about 3 minutes
• There is a Forbes 400 list of richest people which I am not on
• There are 400 grades in a circle

Lastly, the number 400 is the number of articles I have written and posted to the MSDN platform.   This is my 400th.