Owlet puzzle #1
Released Monday, July 6, 2026 UTC
1729
the answer for puzzle #1
The five clues
- A four-digit odd squarefree number famous in number theory.
- It has exactly 8 divisors.
- It is the product of three distinct primes.
- The sum of its digits equals 19.
- Called the taxicab number: the smallest expressible as a sum of two cubes in two ways.
Backstory
1729 = 1³ + 12³ = 9³ + 10³ is the smallest number expressible as a sum of two positive cubes in two different ways — the Hardy–Ramanujan number, from Ramanujan's 1918 hospital-visit remark to G.H. Hardy. It's also a Carmichael number: 1729 = 7 · 13 · 19.
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