The values of the modular j-function at imaginary quadratic arguments
in the upper half plane are usually called singular moduli. In this pa
per, we use the Arakelov intersection to give the prime factorizations
of a certain combination of singular moduli, coming from the Hecke co
rrespondence. Such a result may be considered as a degenerate one of G
ross and Zagier on Heegner points and derivatives of L-series, and is
parellel to the result of Gross and Zagier on singular moduli.