Estimating sequencing depth or mean reads per cell

I have been working with multiple single cell Rna datasets.Inorder to compare the sequencing dpeth of multiple sample,I am trying to find the mean reads per cell.I used the following code:

counts_per_cell <- Matrix::colSums(sample1)
Mean(counts_per_cell)

The value is coming out to be 1392 which is very small.As i am using a publicly available dataset,I dont really know the value to sequencing depth.Can anyone guide me here.How do i find sequencing depth from seurat object?