17:21:25 is also known as the Mavila Major Chord, is constructed using a very flat ~668c subfifth, and an almost neutral 366c third that, when in conjunction with the flat subfifth, starts to have a major sound quality to it. It is well approximated by a number of generally-low accuracy dual-fifth tunings, such as 16 and 23edo.

Chord information
Harmonics 17:21:25
Subharmonics 1/(525:425:357)
Intervals from root 1/121/1725/17
Cents from root 366¢668¢
Step intervals 21/17, 25/21
Step cents 366¢, 302¢
Prime limit 17
Genus 352717 (8925)
Intervallic odd limit 25
Otonal odd limit 25
Utonal odd limit 525
Consistent edos (d ≥ 2) 4edo*, 7edo*, 16edo**, 20edo*, …



Edo approximations for 17:21:25 
intervals: 21/17, 25/17 · ≤ 60edo, RMS rel. error ≤ 15%
  Edo Steps Cents (¢) Absolute errors (¢) RMS (¢) RMS (%)
7 0  2  4 0.00 342.86 685.71 0.00 -22.97 +18.04 16.78 9.79
9 0  3  5 0.00 400.00 666.67 0.00 +34.17  -1.01 16.35 12.26
11 0  3  6 0.00 327.27 654.55 0.00 -38.55 -13.13 16.00 14.67
13 0  4  7 0.00 369.23 646.15 0.00  +3.41 -21.52 11.03 11.95
16 0  5  9 0.00 375.00 675.00 0.00  +9.17  +7.33 3.96 5.28
20 0  6 11 0.00 360.00 660.00 0.00  -5.83  -7.67 3.27 5.45
23 0  7 13 0.00 365.22 678.26 0.00  -0.61 +10.59 5.14 9.85
27 0  8 15 0.00 355.56 666.67 0.00 -10.27  -1.01 4.62 10.40
29 0  9 16 0.00 372.41 662.07 0.00  +6.59  -5.60 4.98 12.04
32 0 10 18 0.00 375.00 675.00 0.00  +9.17  +7.33 3.96 10.57
36 0 11 20 0.00 366.67 666.67 0.00  +0.84  -1.01 0.75 2.26
39 0 12 22 0.00 369.23 676.92 0.00  +3.41  +9.25 3.82 12.42
40 0 12 22 0.00 360.00 660.00 0.00  -5.83  -7.67 3.27 10.90
43 0 13 24 0.00 362.79 669.77 0.00  -3.03  +2.10 2.11 7.55
45 0 14 25 0.00 373.33 666.67 0.00  +7.51  -1.01 3.80 14.24
47 0 14 26 0.00 357.45 663.83 0.00  -8.38  -3.84 3.42 13.41
49 0 15 27 0.00 367.35 661.22 0.00  +1.52  -6.45 3.45 14.11
52 0 16 29 0.00 369.23 669.23 0.00  +3.41  +1.56 1.39 6.03
56 0 17 31 0.00 364.29 664.29 0.00  -1.54  -3.39 1.38 6.46
59 0 18 33 0.00 366.10 671.19 0.00  +0.28  +3.51 1.60 7.85