2025 is a very "squarish" number as the following properties will illustrate:
- 2025=452=272+362
- 2+0+2+5=9=32
- It is divisible by the square of the sum of its digits:
202581=25 - Omitting the zero still leaves a square 225=152
- Omitting the first two digits still leaves a square 25=52
- Adding 1 to the first digit gives the square 3025=552
- Adding 1 to each digit gives the square 3136=562
- Adding 4 at the front gives a square 42025=2052
- 2025 is the smallest square that can be formed from 20 by adding one or more digits
- Square that can be seen on a digital clock as in 20:25
- Written as "twenty twenty five" it has 16=42 letters
- Can be written as a sum of three distinct squares in 9=32 different ways e.g. 42+282+352 ... permalink
- It is the sum of the first nine numbers squared: (1+2+⋯+8+9)2=2025
- Deleting a zero from its cube (8303765625) gives 833765625=288752
- Imagine writing down the number 1 once, the number 2 twice, the number 3 three times, and so on up to the number 45 forty-five times, like this:12233344445555…454545The total number of digits is 2025, which is the square of 45. This coincidence does not occur for any other number greater than 1.
- The sum of entries (in red, below) of a 9×9 multiplication table is 2025:
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