Just the number 1.
25 (25+27+29=81)
They are 'square' numbers. 6x6=36, 9x9=81 and 5x5=25. Some other square numbers are 64, 4, 9, 100 & 121
1 and 81 Those two numbers certainly divide into 81 though they are not the only numbers to do so.
25 and 81
1, 3, 9, 27, 81.
1, 3, 9, 27, 81.
1 3 9 27 81
9. The square root of 81 is 9.
3,
The HCF of both numbers is 1
81 ÷ 28 = 2 with remainder 25.
It must be 81 because 9 squared is 81 and 9 is not a prime number whereas the other numbers are squared prime numbers.