A numerical correlation between the numbers of divisors; the value of the muptiplication of the divisors, and the value of the number It is known that the number of the positive divisors is odd IFF the integer is a square. But it is perhaps less known that it is true for every positive integer (except for those numbers where the number of the divisors is odd and where another rule applies) that N=n^(d(n)/2) where N=the value of the multipication of all divisors n=number d(n)=number of divisors (including the number n itself and 1) E.g. if n=6 and d(n)=4 (since the divisors of 6: 1,2,3,6) then N=6^(4/2)=36 In other words: the multiplication of the divisors result a number that is a power of the number Notice that in the case of the square numbers the equation is sqrt(n)^d(n). E.g. if n=4 then N=sqrt(4)^2 (that is 8). n N d(n) d(n)/2 1 1^1 1 -- (1 has only one divisor, so this is an exception) 2 2^1 3 -- 3 3^1 2 1 4 (2^3) -- 5 5^1 2 1 6 6^2 4 2 7 7^1 2 1 8 8^2 4 2 9 (3^3) 3 -- 10 10^2 4 2 11 11^1 2 1 12 12^3 6 3 13 13^1 2 1 14 14^2 4 2 15 15^2 4 2 16 (4^5) 5 -- 17 17^1 2 1 18 18^3 6 3 19 19^1 2 1 20 20^3 6 3 21 21^2 4 2 22 22^2 4 2 23 23^1 2 1 24 24^4 8 4 25 (5^3) 3 -- 26 26^2 4 2 27 27^2 4 2 28 28^3 6 3 29 29^1 2 1 30 30^4 8 4 31 31^1 2 1 32 32^3 6 3 33 33^2 4 2 34 34^2 4 2 35 35^2 4 2 36 (6^9) 9 -- 37 37^1 2 1 38 38^2 4 2 39 39^2 4 2 40 40^4 8 4 41 41^1 2 1 42 42^4 8 4 43 43^1 2 1 44 44^3 6 3 45 45^3 6 3 46 46^2 4 2 47 47^1 2 1 48 48^5 10 5 49 (7^3) 3 -- 50 50^3 6 3 ... Numbers where d(n) becomes larger than earlier (we can call them using a neologism "ample numbers"): notice that except for 4 and 36, every ample number is even. It is not a surprise, since the square numbers' n(d) is odd. n n(d) 2 2 4 3 6 4 12 6 24 8 36 9 48 10 60 12 120 16 180 18 240 20 360 24 720 30 840 32 1260 36 1680 40 2520 48 5040 60 7560 64 10080 72 15120 80 20160 84 25200 90 27720 96 45360 100 50400 108 55440 120 83160 128 110880 144 166320 160 221760 168 277200 180 332640 192 498960 200 554400 216 665280 224 720720 240 Zoltan Galantai April 22, 2018 (modified: April 28, 2018)