The Talmud (Megillah 14a) says that there had been twice as many prophets as the number of people who left Egypt (2,600,000), but only those whose messages were for future generations were recorded. This count was 48 male and 7 female Prophets.
Of course, there is much debate about who is included in the list. Rashi (Megillah 3a) suggests that Daniel wasn't a prophet and should be replaced by Shemaia, who told Rehavam not to go to war with Yeravam and the northern kingdom. Rabbein Hananel and the Vilna Gaon start from Moshe and add in the sons of Korach.
Rashi also comments that "two [of the prophets] I don't
know," refering to numbers 47 and 48. Another commentator says the missing two prophets are
Oded and Hanani Haroeh.
7 Femal Prophets
46 Male Prophets
Sources: Blackman, Philip. Introduction to Tractate Sanhedrin of the Mishnah. New York: The Judaica Press, 1963; Dimont, Max. Jews, Jews, God and History. New York: The New American Library, 1962; Encyclopedia Judaica "Sanhedrin". Jerusalem: Keter Publishing House, 1971; Kung, Hans. Judaism. New York: Crossroad, 1992; Seltzer, Robert M. Jewish People, Jewish Thought. New York: Macmillian Publishing Co, 1980.