The positive integer "n" is square-free if and only if all abelian groups of order "n" are isomorphic, which is the case if and only if all of them are cyclic.
Prva števila, deljiva brez kvadrata so :: 1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 30, 31, 33, 34, 35, 37, 38, 39, 41, 42, 43, 46, 47, ...== Enakovredne označbe števil deljivih brez kvadrata ==Pozitivno celo število "n" je deljivo brez kvadrata, če in samo, če se v praštevilski razcepitvi "n" nobeno praštevilo ne pojavi več kot enkrat.