DPI: 96 dpi minimum

Use this calculator to find out how many pixels (resolution) an image should have to be printed at a certain size.

Print Dimensions

Net dimensions (no bleed)
508 mm x 287.02 mm = 145806.16 mm2aspect ratio: 1.77 (diagonal: 583.48 mm)
50.8 cm x 28.7 cm = 1457.96 cm2aspect ratio: 1.77 (diagonal: 58.35 cm)
20 inch x 11.3 inch = 226 inch2aspect ratio: 1.77 (diagonal: 22.97 inch)

Print Pixel Size

Dots-per-inch
Printer resolution = 96 dpi = 38 dots/cm
Printer pitch = 265 µm / micrometer (size of 1 pixel)
Net dimensions (no bleed)
1920 px x 1085 px = 2.1 megapixels
= aspect ratio 1.77

Some examples

References