In this paper I try to offer a definitive answer to the question of the relation of Husserl's phenomenology to mathematical Platonism and constructivism of the Brouwerian sort. The controversial issue of Frege's presumed influence on Husserl is also considered and it is briefly argued against such an influence. In the second part of the paper Husserl's semantics of sense and objectuality (or referent) is discussed, and it is shown that it is much more adequate for mathematics than Frege's semantics. Finally, a possible theory of degrees of extensionality is briefly sketched.