Thursday, October 22, 2009

2991

2991 = 3 x 997.

2991 is the smallest number with two prime factors summing to 1000—with three digits the same as the previous number (2491) with prime factors summing to a power of ten: 2491 = 47 x 53.

2991 is a number that cannot be written as the sum of three squares.

2991 is a semiprime that is not the sum of three pentagonal numbers.


Lego set 2991 features Pooh and the Honeybees.
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