Owlet puzzle #90
Released Saturday, October 3, 2026 UTC
210
the answer for puzzle #90
The five clues
- A three-digit squarefree number with four distinct prime factors.
- Equals the product of three consecutive integers: 5·6·7.
- The primes are the first four: 2, 3, 5, 7.
- The primorial of 7.
- Also the twentieth triangular number: T₂₀.
Backstory
The 4th primorial, 2·3·5·7 = 210 — the product of the first four primes. It is also the 20th triangular number T_{20} = 20·21/2 and the smallest positive integer with four distinct prime factors. Every primorial P_n is also the smallest positive integer with exactly n distinct prime factors.
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