Wednesday, February 22, 2012

285

285 = 3 x 5 x 19.

285 is the smallest number whose sum of distinct prime factors is an odd prime to the power of an odd prime: 3 + 5 + 19 = 27 = 33.

285 is 555 in base 7.

285 is a square pyramidal number (the sum of all squares of integers from 1 to 9): 285 = 12 + 22 + 32 + 42 + 52 + 62 + 72 + 82 + 92.

2852 = 81225 uses the same digits as 1352 (18225) and 1592 (25281).


285 is the number of binary rooted trees with 13 vertices.

Source: Prime Curios!

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