Issues converting raster values from mm to cubic meters using raster calculator ArcGIS 10.2

So I have a raster layer of surface runoff in mm/year and I need these values in cubicmeter/year.

I first converted the mm/year values into m/year using raster calculator: (inputraster)*0.001 which worked fine.

My raster cell size is 60000 in meters which makes the area 3600000000 square meters.

I tried to multiply the m/year raster by this value (3600000000) using raster calculator but it keeps giving an error.

Please tell me what I'm doing wrong and what to do.

Below is the error information in the Results window of Geoprocessing section.