The relation R on your question is not an equivalence relation, rather, it is a "partial order" relation.
If R be an equivalence relation, it should satisfy following three conditions.
1. Reflexive ( aRa )
2. Symmetry (if aRb, then bRa)
3. Transitive (if aRb and bRc, then aRc)
(aRb means aRb = TRUE)
Your question satisfies condition 1 and 3 but it does not satisfy the condition 2 ( For instance, 3|6 is true, but 6|3 not ).