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
1 1 68
2 3 41
3 5 40
4 7 37
5 2 35
6 8 33
7 4 31
8 6 31
9 9 31
10 11 27
11 24 20
12 625 20
13 1111 20
14 31 19
15 512 19
16 36 18
17 132 18
18 127 17
19 25 16
20 100 16
21 111 16
22 128 16
23 376 16
24 1019 16
25 12 15
26 15 15
27 23 15
28 27 15
29 32 15
30 144 15
31 179 15
32 225 15
33 1089 15
34 1116 15
35 1296 15
36 1344 15
37 1521 15
38 22 14
39 47 14
40 49 14
41 76 14
42 83 14
43 121 14
44 216 14
45 251 14
46 359 14
47 441 14
48 576 14
49 719 14
50 729 14
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