7
77
717
7117
71817
718817
...
Nobody went out to create them: some numbers simply happen to be palindromic and others don't.
The sum of two palindromic numbers is not necessarily a palindromic number. For example, adding the palindromic numbers 121 and 131 gives 252, which is also a palindrome. However, adding 121 and 122 results in 243, which is not a palindrome. Therefore, while some sums of palindromic numbers can be palindromic, it is not a guaranteed outcome.
There are not just 13 non-palindromic numbers. Most numbers are non-palindromic.
There are 90 palindromic numbers between 100 and 1000
No.
Palindromic numbers occur with varying frequency depending on the range considered. In any given set of numbers, the likelihood of encountering a palindromic number increases as the range expands. For example, among one-digit numbers, all are palindromic, while in larger ranges, the density decreases but still remains significant. Overall, palindromic numbers are not rare and can be found throughout the number system.
infinite
No.
there are 10 palindromic numbers between 9000 and 10000 9009,9119,9229,9339,9449,9559,9669,9779,9889,9999!!!
As 20569.8 is not palindromic, any number that is like it must contain that property and similarly be non-palindromic, so no.
There are more 12-digit palindromic numbers than 11-digit palindromic numbers. This is because the number of possible 12-digit palindromic numbers is greater than the number of possible 11-digit palindromic numbers. In general, the number of palindromic numbers of length n is 9 * 10^((n-1)/2), so for 11-digit palindromic numbers, there are 9 * 10^5 = 900,000 possibilities, while for 12-digit palindromic numbers, there are 9 * 10^6 = 9,000,000 possibilities.
I guess that the smallest would be zero, if you don't consider negative numbers. There is no largest palindromic number - you can make them as large as you like.