Counting 10000, there are 17999.
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There are 3598 numbers between 10000 and 99999 which are divisible by 25. They are elements of the set of numbers of the form 25*k, where k is an integer between 41 and 3999 (inclusive).
The largest 5 digit number is 99999. If this is divided by 11 it leaves a remainder of 9. Therefore the largest 5 digit number divisible by 11 is 99999 - 9 = 99990.
100000
90000. With 10 digit palindromes, the last 5 digits are the same as the first 5 digits in reverse, eg 12345 54321. So it comes down to how many 5 digit numbers are there? They are the numbers "10000" to "99999", a total of 99999 - 10000 + 1 = 90000.
10,000,800,001 is 99999 times 99999.