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 ).