511 Collaboraters

Hungarian Paul Erdős was one of the most famous mathematicians of the twentieth century. Mathematics was a social activity for him, and fellow mathematicians absolutely loved associating with him and collaborating with him. Although he wrote some mathematical papers by himself, most of his approximately 1,525 articles were collaborations with other mathematicians. There are 511 people with an Erdős number of one, which means that 511 people had the privilege of writing at least one paper with him. 511 represents an astounding number of people.

Since I find both Hungary and mathematics quite fascinating, I especially loved reading all about Hungarian mathematician Paul Erdős in the book The Man Who Loved Only NumbersI wish I could have heard him speak while he was still alive.

511 is also the hypotenuse of the Pythagorean triple 336-385-511. Can you find the greatest common factor of those three numbers?

Can you fill in the factors of the following puzzle?

511 Puzzle

Print the puzzles or type the solution on this excel file: 12 Factors 2015-06-01


  • 511 is a composite number.
  • Prime factorization: 511 = 7 x 73
  • The exponents in the prime factorization are 1 and 1. Adding one to each and multiplying we get (1 + 1)(1 + 1) = 2 x 2 = 4. Therefore 511 has exactly 4 factors.
  • Factors of 511: 1, 7, 73, 511
  • Factor pairs: 511 = 1 x 511 or 7 x 73
  • 511 has no square factors that allow its square root to be simplified. √511 ≈ 22.60530911




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