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
501 322 8
502 325 8
503 328 8
504 333 8
505 344 8
506 348 8
507 404 8
508 408 8
509 420 8
510 439 8
511 440 8
512 456 8
513 472 8
514 488 8
515 492 8
516 547 8
517 555 8
518 564 8
519 568 8
520 584 8
521 630 8
522 631 8
523 647 8
524 664 8
525 675 8
526 689 8
527 691 8
528 700 8
529 712 8
530 728 8
531 736 8
532 749 8
533 776 8
534 777 8
535 816 8
536 824 8
537 843 8
538 872 8
539 875 8
540 876 8
541 882 8
542 906 8
543 916 8
544 945 8
545 947 8
546 953 8
547 960 8
548 967 8
549 968 8
550 971 8
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