I agree with buzzb. There are six squares, but 1 and 16 are also the two fourth powers. Associating property c with 1 and 16 means that property a must be associated with 4, 9, 25 and 36.
I found it useful to prepare a grid of all 38 clue numbers and the 20 properties, showing which properties were satisfied by each number (for example, 1 satisfies as many as eight of the properties). This grid showed that some numbers satisfied only one property while other properties (for example, property c, the fourth power, and property n, the perfect number) were satisfied by exactly the number of answers shown in my grid. Using the limitations imposed by the number of cells in each answer and avoiding "leading zeroes", this allowed me to fill in 24, 17, 30, 6, 28, 27, 32, 8, 1 and 5 fairly quickly.
However, without the various lists of numbers on the internet (particularly lists of prime numbers), this puzzle would have been much harder. However, it's all come out nicely after around four hours of work.