Convert from petagram to millimass unit

Unit Definition (petagram)
The petagram is a metric unit of mass equal to 10E15 grams or 1 gigatonne (one billion metric tons). This unit is used in atmospheric science and other scientific contexts where large masses are considered.

Unit Definition (millimass unit)
The millimass unit is a unit of mass equal to 0.001 atomic mass unit, used in physics and chemistry. This unit is also called the millidalton (mDa). The millimass unit is an SI unit, but its proper SI symbol is mu, not the older symbol mmu.