The value of conductivity of some materials at \( 298.15 \, \text{K} \) in \( \text{S m}^{-1} \) are \( 2.1 \times 10^{3} \), \( 1.0 \times 10^{-16} \), \( 1.2 \times 10 \), \( 3.191 \), \( 1.5 \times 10^{-2} \), \( 1 \times 10^{-7} \), \( 1.0 \times 10^{3} \). The number of conductors among the materials is ________.