# What is the significance of the number "1729"?

This is Srinivasa Ramanujan's Lucky Number

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Hardy's dull number Ramanujan's interesting (and lucky?) number.

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• It is the first number that can be expressed as sum of cube of 2 different set of 2 numbers

12^+1^3=1728+1=1729

9^3+10^=729+1000=1729

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• I have no idea except 1729 = 1000+729 = 10^3 + 9^3 = 19 x 91 = 19 x13x7. So it is a bit interesting since two of its factors are 7 and 13. Also, 29-17= 12 and 12^3 = 1728, and 10^3+9^3 =12^3 +1^3. He liked number theory.

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• It is the sum of cube of 9 & cube of 10. (9^3 + 10^3 = 1729)

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• 1 x (7+2) = 9

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• Anonymous

1 is the fact you are first as in being #1. 7 is the old lucky number to gamble on. 2 is how many it takes to tango, and 9 is what you get when you add 2 that are getting lucky (7) and nine is the outcome of the addition.

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• It was the number of the cab used by Hardy when he came to visit Ramanujan, and became a topic of conversation between the two.

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• This is the smallest number that can be expressed as sum of 2 cubes in 2 different ways(10,9) and(12,1)

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• Agree

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• Anonymous
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