Spanish Jews of Constantinople, 1833

This missionary report claimed that Constantinople had the largest Jewish population of any city in the world in 1833. I suspect this is incorrect.

"The Jews at Constantinople [Istanbul] are variously estimated at from 40,000 to 80,000. The number is uncertain, but it is believed that more Jews are collected there than at any other place of their dispersion. … Having come originally from Spain on the expulsion of the Jews from that country, their language is corrupted Spanish which is written in the Spanish Rabbinical letter; differing from the German Rabbinic and still more from the Hebrew letter. Their language contains a mixture of Spanish and Hebrew words. …
…
The Jewish boys attend school for several years, but not the girls. Instances where males cannot read are rare, as rare is to find a female reader."

Source: William G. Schauffler, Missionary. Mission to the Jews of Turkey. Annual report - American Board of Commissioners for Foreign Missions: Volumes 24-26. 1833. Page 45