The greatest common denominator is infinite.
There can be no greatest common denominator. Suppose x is the greatest common denominator. That requires that 39 divides x, 26 divides x and x is the greatest such number. But 39 will divide 2x and 26 will divide 2x and 2x is greater than x. So x could not have been a GCD.
The greatest common denominator of any two numbers is infinite.
The Greatest Common Factor of 26, 39, 52: 13
The Greatest Common Factor of 13, 39, 26 is 13.
The greatest common factor of the numbers 39, 13 and 26 is 13.
The greatest (and indeed only) common factor of 26, 36, and 39 is 1.
The Greatest Common Divisor/Denominator is 39
The Greatest Common Divisor/Denominator is 39
The GCF of 26 and 39 is 13.
The least common denominator (LCD) is 1.
The Greatest Common Factor (GCF) is: 13
The GCF of 26, 39, and 78 is 13.