11
Yes.
It is not clear what the question means: there are 31 2-digit numbers that can be expressed as a sum of two squares.
Total number of 2-digit numbers = (99 - 9) = 90 of themEvery number that isn't a perfect square has an even number of factors.2-digit numbers that are perfect squares: 16, 25, 36, 49, 64, and 81 = 6 of themRemaining 2-digit numbers = (99 - 6) = 93 .
52925 53035
11
1 to 1000. Pilandromic 108
Yes.
The only 2-didgit palindromic prime is 11.
It is not clear what the question means: there are 31 2-digit numbers that can be expressed as a sum of two squares.
Total number of 2-digit numbers = (99 - 9) = 90 of themEvery number that isn't a perfect square has an even number of factors.2-digit numbers that are perfect squares: 16, 25, 36, 49, 64, and 81 = 6 of themRemaining 2-digit numbers = (99 - 6) = 93 .
52925 53035
There are the same number: any twelve digit palindrome is just an eleven digit palindrome with its central digit repeated. In general, if we are considering numbers of n digits: For even values of n, the number of palindromes is 9 x 10n/2 - 1 For odd values of n, the number of palindromes is 9 x 10(n-1)/2
The squares of most 2 digit prime numbers. For example 2809, which is the square of 53, has 3 factors : 1, 53 and 2809 itself.
A 3 or 4 digit number.
It is 77.It is 77.It is 77.It is 77.
There are 28706 such combinations. 5456 of these comprise three 2-digit numbers, 19008 comprise two 2-digit numbers and two 1-digit numbers, 4158 comprise one 2-digit number and four 1-digit numbers and 84 comprise six 1-digit numbers.