Interestingness score

How we rank numbers on NumDic

How it’s calculated

Each number gets a score from the properties shown on its page (number-theory characteristics and base-10 digit properties):

  • Base: +1 point for every property chip (e.g. Prime, Triangular, Palindromic).
  • Bonus (rare): +3 for very special properties: Mersenne, Mersenne prime, Fermat number, Catalan number, Dudeney number, Perfect, Narcissistic.
  • Bonus (medium): +2 for other notable ones: Sophie Germain prime, Safe prime, Layland, Factorial, Pandigital, Strobogrammatic, Refactorable, Powerful number, Lucas number, Gaussian prime, Kaprekar, Smith, Automorphic, Trimorphic, Hoax number, Zuckerman number.

The total is the interestingness score. Higher means more properties and/or rarer ones. On each number page you also see how many chips are in each section.

Example

Number 6 has a score of 31.

It has the following properties (each contributing base points and possibly bonus):

Triangular, Hexagonal, Evil number, Pronic, Factorial, Even, Ones-Zeroes, Palindromic, Harshad, Repdigit, Automorphic, Spy number, Narcissistic, Trimorphic, Zuckerman number, Composite, Perfect

Plus the usual classification (Prime/Unit/Composite) and, when applicable, Perfect/Abundant/Deficient and Twin Prime.

Top 1000 most interesting numbers

Precomputed list; same order as on number pages (by score, then by number). Paginated 50 per page.

Rank Number Score
801 1891 7
802 1904 7
803 1905 7
804 1933 7
805 1976 7
806 34 6
807 35 6
808 50 6
809 52 6
810 61 6
811 65 6
812 68 6
813 73 6
814 92 6
815 97 6
816 102 6
817 124 6
818 129 6
819 130 6
820 137 6
821 141 6
822 148 6
823 149 6
824 150 6
825 161 6
826 170 6
827 188 6
828 189 6
829 195 6
830 197 6
831 205 6
832 213 6
833 219 6
834 229 6
835 235 6
836 236 6
837 241 6
838 253 6
839 260 6
840 262 6
841 264 6
842 269 6
843 270 6
844 285 6
845 287 6
846 291 6
847 292 6
848 302 6
849 304 6
850 305 6