Maryam, 19

The number

19

a prime number only divisible by number 1 (the starter) and itself (the ending)

[19] - Surah Maryam (Chapter of Mary)

A Qur'anic mentioned of Maryam

Mary (Arabic: مريم‎, translit. Maryam‎), the mother of Jesus (Isa), holds a singularly exalted place in Islam as the only woman named in the Quran, which refers to her seventy times and explicitly identifies her as the greatest of all women,[2][3][4] stating, with reference to the angelic saluation during the annunciation, "O Mary, God has chosen you, and purified you; He has chosen you above all the women of creation."[5] In the Quran, her story is related in three Meccan chapters (19, 21, 23) and four Medinan chapters (3, 4, 5, 66), and the nineteenth chapter of the scripture, the Chapter of Mary (Surat Maryam), is named after her. The Quran refers to Mary more than the entire New Testament.[6]

(reference : https://en.wikipedia.org/wiki/Mary_in_Islam)

The moon will appear in the exact position among the stars every 19^th year. 

The lunar and solar cycles coincide every 19 years