Friday, January 25, 2013

2225

2225 = 5 x 5 x 89.

2225 has three representations as a sum of two squares (A025313 and A000443): 2225 = 42 + 472 = 172 + 442 = 252 + 402.

2225 is the hypotenuse of two primitive Pythagorean triples: 22252 = 3762 + 21932 = 14962 + 16472.

2225 is a value of n where the sum of the nth powers of its digits are prime for n = 1 to 10: 21 + 21 + 21 + 51 = 11, 22 + 22 + 22 + 52 = 37, and so on.


Source: Prime Curios!

1 comment:

Anonymous said...

The last property is sated in a confusing manner (the first n has nothing to do with the two other n's in the same sentence) and it should be stated rather as follows: «2225 has the following property: the sums [in the plural!] of the nth powers of its digits are prime for n = 1 to 10 [...]»