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
401 811 9
402 818 9
403 820 9
404 823 9
405 825 9
406 827 9
407 855 9
408 856 9
409 859 9
410 883 9
411 896 9
412 919 9
413 1013 9
414 1035 9
415 1048 9
416 1068 9
417 1087 9
418 1096 9
419 1115 9
420 1124 9
421 1128 9
422 1164 9
423 1184 9
424 1208 9
425 1224 9
426 1229 9
427 1231 9
428 1236 9
429 1279 9
430 1289 9
431 1291 9
432 1368 9
433 1409 9
434 1416 9
435 1430 9
436 1447 9
437 1448 9
438 1476 9
439 1483 9
440 1484 9
441 1524 9
442 1528 9
443 1548 9
444 1572 9
445 1575 9
446 1601 9
447 1632 9
448 1656 9
449 1663 9
450 1667 9