A numerical milestone, no foolin'
Aziz Inan
Issue date: 4/2/09 Section: Opinions
This year's April Fools' Day is one of a kind, and believe it or not, this claim is not an April Fools' prank! April 1, 2009, when expressed as the full date number 4012009, is a "perfect square date" because it equals square of 2003.
A perfect square date is defined as a full date number given by MMDDYYYY (an eight-digit number where the first two digits are the month, the next two are the day and the last four are the year numbers) that is a perfect square. For example, Sept. 1, 2004 is a perfect square date since 9012004 equals square of 3002. Indeed, this date is the first perfect square date of the 21st century, which largely went unnoticed. The second and the third perfect square dates of this century both fall in this year.
The second occurred less than a month ago on March 5, 2009 (since 3052009 equals to the square of 1747) and the third one is April Fools' Day.
It is very special indeed for a perfect square April Fools' date to occur in one's lifetime, since the next one will occur 4007 years from now, in 6016 (4016016 equals the square of 2004). Also, before this year's April Fools' Day, the first perfect square April 1st day occurred 1053 years ago in 956 (401956 is square of 634) long before the April Fools' tradition began. (Note that a date in a three-digit year is represented by a seven- instead of an eight-digit number).
Perfect square dates are generally very rare and don't occur every year. In fact, there were only a total of two perfect square dates in the 18th century, two in the 19th century and four in the 20th century.
Perfect square dates can only occur in years ending with double zeros, 1, 4, 6, 9 or 25. Additionally, if the year ends with 00, the preceding digits of the year must be a square number; if it ends with 1, the preceding digits must be divisible by 4; if it ends with 4, the preceding digit must be even; if it ends with 25, the preceding digits must be 0, 2, 06, or 56; if it ends with 6, the preceding digit must be an odd number; and if it ends with 9, the preceding digits must be divisible by 4. Wow!
A perfect square date is defined as a full date number given by MMDDYYYY (an eight-digit number where the first two digits are the month, the next two are the day and the last four are the year numbers) that is a perfect square. For example, Sept. 1, 2004 is a perfect square date since 9012004 equals square of 3002. Indeed, this date is the first perfect square date of the 21st century, which largely went unnoticed. The second and the third perfect square dates of this century both fall in this year.
The second occurred less than a month ago on March 5, 2009 (since 3052009 equals to the square of 1747) and the third one is April Fools' Day.
It is very special indeed for a perfect square April Fools' date to occur in one's lifetime, since the next one will occur 4007 years from now, in 6016 (4016016 equals the square of 2004). Also, before this year's April Fools' Day, the first perfect square April 1st day occurred 1053 years ago in 956 (401956 is square of 634) long before the April Fools' tradition began. (Note that a date in a three-digit year is represented by a seven- instead of an eight-digit number).
Perfect square dates are generally very rare and don't occur every year. In fact, there were only a total of two perfect square dates in the 18th century, two in the 19th century and four in the 20th century.
Perfect square dates can only occur in years ending with double zeros, 1, 4, 6, 9 or 25. Additionally, if the year ends with 00, the preceding digits of the year must be a square number; if it ends with 1, the preceding digits must be divisible by 4; if it ends with 4, the preceding digit must be even; if it ends with 25, the preceding digits must be 0, 2, 06, or 56; if it ends with 6, the preceding digit must be an odd number; and if it ends with 9, the preceding digits must be divisible by 4. Wow!