The computer in NORAD is made up from components of an actual IBM AN/FSQ-7 Combat Direction Central, built in 1954 to protect the US from Soviet bomber attack. Components of decommissioned systems were sold for scrap and bought by film and television production companies that wanted futuristic-looking computers, despite the fact they were built in the 1950s. Components used in this film were previously used in The Time Tunnel (1966), The Towering Inferno (1974) and WarGames (1983), among many others, and later used in Fail Safe (2000).
When practicing their bombing run on Irkutsk, they simulate flying over the city at heading 230, and Cassidy quips "Right down Karl Marx Street". This is actually accurate: Irkutsk does have a Karl Marx Street, and its heading - when going to the south east - is in fact approximately 230.
The Emergency War Order code sent to launch the Strategic Air Command's long-range bombers depicted by the movie was "Alpha-Golf-Hotel-India-Delta" with an authentication time of "20:06:05 Zulu" and an authentication of "Sierra-Foxtrot."