“A perfect number N has the property that if you add up all the smaller numbers that divide N you get N back. 28=1+2+4+7+14 or 6=1+2+3.”
“I tried to persuade Charles Clarke to propose a private members bill in parliament to make 28 of June “the perfect day” to celebrate maths.”
“The next perfect number is 496 so perhaps we should have celebrated the perfect day in 496 AD. What was happening then I wonder?”
“Are perfect numbers useful? Probably not but who said maths had to be useful. Is Bach’s Goldberg Variations useful?”
“If 2^n-1 is a prime then 2^{n-1}(2^n-1) is a perfect number. 7=2^3-1 which gives the perfect number 28=2^{3-1} x 7=4 x 7.”
From…
MarcusduSautoy
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