The Number 1639: Properties and Meanings
is a Nonagonal Number
is a Centered 18-gonal Number
is the number of binary rooted trees with 16
The Year 1639 AD
There was a Venus Transit in 1631
AD and a partner transit in 1639
In the year 1639
AD Stefano Landi, Italian composer died.
Melchior Franck, German composer died.