There are 99 ayaat in Surah Maryam and it is a ‘makki’ surah, by makki, it means it was revealed in Mekkah.
It is written in the commentary of Majma’ul Bayan that the reward for reciting Surah Maryam is equal to ten times the number of people present at the time of Prophet Zakariyyah (a.s.), Yahya (a.s.), Isa (a.s.), Musa (a.s.), Ishaq (a.s.), Harun (a.s.), Ibrahim (a.s.), Ya’qub (a.s.) and Isma’il (a.s.) combined.
Keeping Surah Maryam (written) in the house also ensures protection from thieves and Allah (s.w.t.) blesses the occupants of the house.
It is also narrated that before going in the presence of a tyrant ruler, if a person recites ‘Kaf-Ha-Ya-’Ain-Saad’ and closed, with each letter, one finger of his right hand, and then recites ‘Ha-Mim-‘Ain-Seen-Qaaf’ and with each letter, closes one finger of his left hand; and then he comes in the presence of the tyrant and recites ‘wa ‘anatil wujuhu lil hayyil qayyum wa khaaba man hamala dhulma’ and then he opens his fingers, he will be protected from the evil of the tyrant.
Jazakallah Khairan Katheeran
And Allah Knows Best!