Number Gossip

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Unique Properties of 89

  • 89 is the smallest number for which the positive sum of all odd primes less than or equal to it is a square
  • 89 is the first and only multi-digit prime p such that the sum of its digits powered to 1, 2, ... (as the position of the digit from left to right) is equal to p: 89 = 81 + 92
  • 89 is the smallest prime that is a concatenation of pq and qp where p and q are prime
  • 89 is the smallest prime with all digits containing holes
  • 89 is the smallest prime whose digits are composites
  • 89 is the only two-digit number that is the sum of its first digit and its second digit squared

Rare Properties of 89

Fibonacci

Common Properties of 89

Deficient
Evil
Odd
Prime
Square-free