13th root 13th root of a 100-digit number. All world records for mentally extracting a 13th root have been for numbers with an integer root. 13th root Extracting the 13th root of a number is a famous category for the mental calculation world records. The challenge consists of being given a large number (possibly over 100 digits) and asked to return the number that, when taken to the 13th power, equals the given number. For example, the 13th root of 8,192 is 2 and the 13th root of 96,889,010,407 is 7. Extracting the 13th root has certain properties. One is that the
Palindromic number types of palindromic numbers these values are listed below in a table. Here 0 is included. There are many palindromic perfect powers "n", where "n" is a natural number and "k" is 2, 3 or 4. The first nine terms of the sequence 1, 11, 111, 1111, ... form the palindromes 1, 121, 12321, 1234321, ... The only known non-palindromic number whose cube is a palindrome is 2201, and it is a conjecture the fourth root of all the palindrome fourth powers are a palindrome with 100000...000001 (10 + 1). G. J. Simmons conjectured there are no palindromes of form