Monday, February 25, 2013

489

489 = 3 x 163.

489 is the smallest number ending in 1, 3, 7, or 9 that cannot be made prime by adding any multiple of 100 up to 700. In other words, 589, 689, 789, 889, 989, 1089, and 1189 are all composites.

489 is an octahedral number (A005900).

489 is the number of primes less than 3,500 (A028505).

489 is the sum of five positive fifth powers (A003350): 489 = 35 + 35 + 15 + 15.


Source: Prime Curios!

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