Hi, smellyharry,
I don't think that there is any particular virtue in
not using tools such as spreadsheets for numerical puzzles like this. For this puzzle, I also made use of online lists of prime numbers (particularly useful for the answer to 37, a five-digit prime). I prepared a spreadsheet list of diagonal numbers for property o and tetrahedral numbers for property h, and also for sums of two non-zero squares, so didn't bother with the prime factorisation approach suggested by the preamble. Some other online lists, such as Fermat and Mersenne primes, were useful.
I'm more relaxed about using spreadsheets for numerical puzzles than using anagram solvers and similar tools for word-based puzzles, but I must admit that I sometimes make use of these aids when stuck.
The thing I find most helpful is to write down every step of my reasoning, so that, if I run into contradictions or dead ends, I can go back and spot where I went wrong.
Although on my first run through this puzzle, I associated properties with clue numbers as I went, I did a second run and found that I could associate all but eight clues with a specific property (allowing for the two properties associated with 10 and with 23) without actually solving any of the clues. I'm not sure that this was much quicker than the more ad hoc approach, but I think the logic is more elegant.