How a number with +45 is written
International format: +45 3X XX XX XX
National format: 3X XX XX XX
Denmark has no trunk prefix: the national number follows +45 unchanged.
Mobile number length: 8 digits after +45
Calling a Denmark number from abroad
From another country, dial + (or your exit code: 00 in most of the world, 011 from North America), then 45, then the national number without its trunk prefix.