A numerical tautonym is traditionally defined as a word which can be divided into a sequence of at least two (adjacent) parts, where each part has both the same number of letters as well as the same alphabetic value sum (see David Morice, The Dictionary of Wordplay). For example, the four letters in the word THIS can be transposed into the corresponding numbers 20-8-9-19 (where A = 1, B = 2...Z = 26), which can be divided in the two parts 20-8 and 9-19. If the numbers in the first part are added together, then we obtain 28, which is precisely the sum of the two numbers in the second part. Note that the two-part numerical tautonym THIS is 'balanced' in two respects: The numerical value of each of the two parts is identical, as is the number of letters in each part.
"Tripartitle Numerical Tautonyms,"
Word Ways: Vol. 45
, Article 16.
Available at: https://digitalcommons.butler.edu/wordways/vol45/iss2/16