Forty-seven is the fifteenth prime number, a safe prime, the thirteenth super singular prime, and the sixth Lucas prime. Forty-seven is a highly cototient number. It is an Eisenstein prime with no imaginary part and real part of the form 3n – 1. Its representation in binary is 00101111.  47 is a prime Thabit number, and as such is related to the pair of amicable numbers {17296, 18416}.

On the day Susan Wight was born, so were Gideon Henderson (geologist), Paavo Lötjönen (cellist), and Rodney Allen Rippy (actor).

47 years ago today, Pope Paul VI reiterated his prohibition of the use of the birth control pill for Roman Catholics, as well as all other contraception.

Also on this day in 1968, Mount Arenal in Costa Rica killed 80 people in a Pelee-type eruption. (I think we can all agree 47 would have been a better, if creepier, number of casualties.)

It took the U.S. Postal Service 47 years to deliver a postcard from Montana to Ohio (the sender and the recipient both died before it arrived in 2009.)

If people are asked to pick a random number, 47 is the most common one chosen.

Julia Roberts, Céline Dion and Traci Lords are all 47.

In the 1960’s, Professor Donald Bentley of Pomona College completed a mathematical proof which stated that all numbers are equal, therefore all numbers are equal to 47. A Pomona College alum became a writer for Star Trek The Next Generation. He convinced the other writers and producers to put a reference to the number 47 in every episode.

47 is the telephone country code for Norway.

The Tropic of Cancer and the Tropic of Capricorn are located 47 degrees apart.

Mel Blount (#47) won 4 Super Bowls with the Pittsburgh Steelers, was a 5x Pro Bowler, a member of the Pro Football Hall of Fame, and is arguably the best cornerback in the history of the NFL.

47 would be an incredible, pricey age for a Scotch. Like that Scotch, Susan is more valuable and fascinating every year.

Happy Birthday Susan.