Fatto generale: 39 is the duration, in nanoseconds, of the nuclear reaction in the largest nuclear explosion ever performed (Tsar bomb).
Fatto matematico: 39 is the 12th distinct semiprime and the 4th in the {3.q} family.
Trivia: 39 is the number of mentions of work or labor in the Torah.
Data storica: February 8th is the day in 1971 that South Vietnamese ground troops launch an incursion into Laos to try to cut off the Ho Chi Minh trail and stop communist infiltration.