Number Gossip

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Unique Properties of 1729

  • 1729 is a Ramanujan number, also called a taxi-cab number, the smallest number representable in two ways as a sum of two cubes: 1729 = 13+123 = 93+103
  • 1729 is the smallest number that is a pseudoprime simultaneously to bases 2, 3 and 5
  • Web pages about 1729:
  • 1729 is the smallest Carmichael number n such that n-1 is a perfect power
  • 1729 is the smallest Carmichael number whose prime factors form an arithmetic progression
  • 1729 is the product of the first three happy primes
  • 1729 is the smallest Carmichael number such that its Euler totient function is a perfect square
  • 1729 is the smallest phi-radical number: composite number n such that rad(φ(n)) = rad(n-1)

Rare Properties of 1729


Common Properties of 1729