The first order rate constant for the decomposition of \( \mathrm{CaCO_3} \) at \( 700 \,\mathrm{K} \) is \( 6.36 \times 10^{-3} \,\mathrm{s^{-1}} \) and activation energy is \( 209 \,\mathrm{kJ\, mol^{-1}} \). Its rate constant (in \( \mathrm{s^{-1}} \)) at \( 600 \,\mathrm{K} \) is \( x \times 10^{-6} \). The value of \( x \) is _______. (Nearest integer)
[Given : \( R = 8.31 \,\mathrm{J\, K^{-1}\, mol^{-1}} \); \( \log 6.36 \times 10^{-3} = -2.19 \), \( 10^{-4.79} = 1.62 \times 10^{-5} \) ]