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
51 999 14
52 1332 14
53 1439 14
54 1600 14
55 17 13
56 55 13
57 72 13
58 81 13
59 85 13
60 88 13
61 96 13
62 99 13
63 107 13
64 108 13
65 120 13
66 125 13
67 191 13
68 239 13
69 361 13
70 383 13
71 645 13
72 720 13
73 808 13
74 861 13
75 1000 13
76 1024 13
77 1031 13
78 1152 13
79 1212 13
80 1487 13
81 1800 13
82 1812 13
83 1881 13
84 1903 13
85 1908 13
86 2000 13
87 16 12
88 18 12
89 28 12
90 29 12
91 59 12
92 64 12
93 84 12
94 131 12
95 136 12
96 153 12
97 167 12
98 199 12
99 202 12
100 227 12