Monday, April 2, 2012

646

646 = 2 x 17 x 19.

646 is a divisor of 696 - 1.

646 is the number of connected planar graphs with 7 vertices (A003094).

646 is 787 in base 9.

646 is the sum of seven positive fifth powers: 646 = 35 + 35 + 25 + 25 + 25 + 25 + 25.

Source: What's Special About This Number?
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1 comment:

  1. StuApril 2, 2012 at 9:48 PM

    I'm sorry - I can't help but comment. What's special about 646? - it's the hull number of one great (former) submarine: USS GRAYLING (SSN 646) - Fast Attack Tough!! :-)

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