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
901 610 6
902 620 6
903 621 6
904 623 6
905 629 6
906 635 6
907 649 6
908 655 6
909 661 6
910 665 6
911 671 6
912 673 6
913 696 6
914 697 6
915 701 6
916 705 6
917 711 6
918 716 6
919 717 6
920 730 6
921 737 6
922 740 6
923 741 6
924 747 6
925 748 6
926 750 6
927 757 6
928 760 6
929 763 6
930 767 6
931 768 6
932 770 6
933 782 6
934 783 6
935 790 6
936 793 6
937 797 6
938 802 6
939 805 6
940 806 6
941 807 6
942 810 6
943 812 6
944 821 6
945 829 6
946 832 6
947 836 6
948 847 6
949 848 6
950 857 6