Numberdolorido

Numberdolorido is a fictional mathematical concept used primarily in online puzzle communities and collaborative fiction to categorize numbers by their digit-sum property. It is not part of formal mathematics.

The term blends "numero" and "dolorido," and is sometimes explained as numbers bearing the "mark" of their digits. In many discussions, it is used humorously to designate a class of numbers in riddles and games, rather than as a rigorously defined mathematical category.

In most uses, a numberdolorido (ND) is a natural number whose digits in base-10 sum to a prime number. For example, 14 has digits 1 and 4, whose sum is 5, a prime, so 14 is ND. 37 sums to 10, which is not prime, so 37 is not ND. 101 sums to 2, which is prime, so it is ND as well.

Properties and usage: There is no single canonical list of ND numbers, and the class is infinite, including many two- and multi-digit numbers. The notion is mainly employed for classification in puzzles, games, or lightweight explorations of digit-based properties, rather than as a formal mathematical theory. It helps create solvable constraints in challenges or serve as a playful example when discussing digit sums.

Related concepts include digital sum and digit-sum properties discussed in recreational number theory, such as the study of how digit sums relate to primality or to other digit-based characteristics.

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