1, 9, and 81 are the only multiples of 81
81, 162, 243, 324, etc.
The first four multiples of 81 are 81, 162, 243, and 324.
81, 162, 243 and so on.
81, 162, 243, 324
1, 3 and 9 are common factors of 27, 45 and 81. 27, 45 and 81 are multiples of 1, 3 and 9.
Every multiple of 81 is also a multiple of 27.
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The multiples of 243 is 1, 3, 9, 27, 81, and 243.
Common multiples include any multiple of 405.
28-81 is greater
Techcially all numbers are divisible by 81, however many would result in a decimal answer. If you mean how many numbers are divisible by 81 and have an integer answer, then it is "all multiples of 81" - e.g 81 x 2, 81 x 3 etc...81, 162, 243 and keep adding 81 forever.