1987
This number is a prime.
A supernova (SN1987a) became visible to earthlings in the year 1987.
The year Noam Elkies proved that an elliptic curve over the rational numbers was supersingular at infinitely many primes.
The Fermat Prize for Mathematics Research started in 1987. It rewards the work of one or more mathematicians in fields where the contributions of Pierre de Fermat have been decisive: statements of variational principles, foundations of probability and analytical geometry, and number theory.
The concept of self-organized criticality (SOC) was put forward by Per Bak, Chao Tang and Kurt Wiesenfeld in a paper published in 1987 and is considered to be one of the mechanisms by which complexity arises in nature. [Jackson]
The Kauaʻi ʻōʻō (Moho braccatus) of the Mohoidae family of birds was last heard in 1987. [Harber]
The 1987 book "Hans Jacob Honegger: From Switzerland to America" by Nadine W. Larson is about a carpenter who changed his last name from Honegger to Honaker. (Honaker primes are named in his honor.)
The largest number in a Collatz trajectory is 9232 for 1987 different numbers. [Gaydos]
There are 1987 ways to place four non-attacking chess kings on a 5 × 5 board. [Astudillo]
The smallest prime p for which p and p^3 have the same sum of cubes of digits. [Gaydos]
1987^2 is the 40th square having a sum of digits equal to 40. [Gaydos]