1729 - Hardy–Ramanujan Taxicab Number

1729 is famous because it can be written as the sum of two cubes in two different ways.

Why this number matters

It is one of the best-known stories in number theory and shows that numbers can hide surprising patterns.

Background / history

G. H. Hardy mentioned taxi number 1729 to Ramanujan, who immediately recognized its special cube property.

Simple example

1729 = 1³ + 12³ and also 9³ + 10³.

Key Facts

Fun fact

1729 is called the first taxicab number.

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