The number 1106 in white appears on recto. Titled "Rey" on verso by what may be the hand of Antoin Sevruguin. Also a description in French on verso.
Publications
Myron Bement Smith Collection: Antoin Sevruguin Photographs. Freer Gallery of Art and Arthur M. Sackler Gallery Archives. Smithsonian Institution, Washington D.C. Gift of Katherine Dennis Smith, 1973-1985. Museum number: FSA A.4 2.12.GN.26.08.Titled: "Shahr-i Ray (Iran): North side of Naqar Khana". The number "1106" appears in white on recto, but has been scratched out in black ink.
Michael Myers Shoemaker, "The Heart of the Orient", New York: The Knickerbockers Press, 1904, p:169
The image is reproduced on page 265 of Volume III of “Du Khorassan au pays des Backhtiaris: trois mois de voyage en Perse” by Henry-Rene D’Allemagne published in 1911 by Hachette, Paris, France. The image is titled "Tour en ruines aux environs de Teheran".