Question

what is ramanujan number explain one page

Answer 1

 was a professor of mathematics at Cambridge University. One day he went to visit a friend, the brilliant young Indian mathematician Srinivasa Ramanujan, who was ill. Both men were mathematicians and liked to think about numbers.

When Ramanujan heard that Hardy had come in a taxi he asked him what the number of the taxi was. Hardy said that it was just a boring number: 1729. Ramanujan replied that 1729 was not a boring number at all: it was a very interesting one. He explained that it was the smallest number that could be expressed by the sum of two cubes in two different ways.

This story is very famous among mathematicians. 1729 is sometimes called the “Hardy-Ramanujan number”.

There are two ways to say that 1729 is the sum of two cubes. 1x1x1=1; 12x12x12=1728. So 1+1728=1729 But also: 9x9x9=729; 10x10x10=1000. So 729+1000=1729 There are other numbers that can be shown to be the sum of two cubes in more than one way, but 1729 is the smallest of them.

Answer 2

1729
the smallest number that could be expressed by the sum of two cubes in two different ways
1729 = 13 + 123 = 93 + 103