Thursday, July 23, 2009

250

250 = 2 x 53.

250 has two representations as a sum of two squares: 250 = 52 + 152 = 92 + 132.

250 is the smallest multidigit number such that the sum of the squares of its prime factors equals the sum of the squares of its digits.

1
3 + 33 + 33 = 55, 53 + 53 = 250 and 23 + 53 + 03 = 133.

250 is 505 in base 7.


In the year
250, Diophantus writes Arithmetica, the first systematic treatise on algebra.

Source:
The Penguin Dictionary of Curious and Interesting Numbers, rev. ed., by David Wells.

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