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Ramanujan Magic Number Riddle

Ramanujan Magic Number Riddle - 22 July

Ramanujan discovered 1729 as a magic number.

Why 1729 is a magic number ?

For Solution : Click Here

10 comments:

  1. 1729 is the smallest number that can be expressed as the sum of cubes of two different numbers in two different ways.
    1729 = 10ᶟ + 9ᶟ
    1729 = 12ᶟ + 1ᶟ

    ReplyDelete
    Replies
    1. it is the smallest 'positive' number that can be expressed as a sum of two cubes in two different ways.The smallest number is 93
      3^3+4^3=93
      -5^3+6^3=93

      Delete
    2. Lol....
      3^3 + 4^3 is 91
      But should be expressed as sum of 2 positive cubes..

      Delete
  2. sum of cubes of two different numbers in two different ways.
    10^3+9^3=1729
    12^3+1^3=1729

    ReplyDelete
  3. 1729 is the lowest number that is a sum of 2 cubes and can be expressed in two ways:
    1729=1728+1
    1729=1000+729

    ReplyDelete
  4. 1729 is the product of two primes i.e 13 and 133

    1729= 13 *133.
    It is also product of two peculiar Numbers, (where, one number can be obtained by simply interchanging the digits of other Number)

    1729 = 19 * 91

    ReplyDelete
    Replies
    1. 1729 = 7 ×13 × 19
      Product of 3 prime numbers

      Delete
  5. Sorry. 133 is not a prime though.These two are funny numbers.We get 133, by adding '3' to the right of '13' Or get '13' by removing any '3' from '133'.
    Our 1729 is perhaps considered a magic Number. because it is the Product of '13' and '133'.

    ReplyDelete
  6. 1 + 7 + 2 + 9 = 19
    19 × 91 = 1729

    ReplyDelete