Let p, q and \(q'\) be three distinct odd prime numbers, satisfying certain congruences. We give the structure of the unramified abelian Iwasawa module \(X_{\infty }(\mathbb {Q}(\sqrt{pqq'}))\) of the number field \(\mathbb {Q}(\sqrt{pqq'})\) . As an example, for \(q=2^{82589933}-1\) and \(q'=2^{136279841}-1\) , the recently discovered prime numbers, we have: \( X_{\infty }(\mathbb {Q}(\sqrt{13qq'}))\simeq (\mathbb {Z}/2\mathbb {Z})^{2^{82589931}}. \)