I happened to see few interesting facts through a WhatsApp forward about 2019 - it is the smallest 4 digit number which can be expressed as a sum of three prime squares in six different ways
That egged me to write a small blog for 2019 as we welcome the New Year!
Look at all perfect squares from 10 to 100 in steps of 10 - 100, 400, 900 and so on and add or subtract to arrive at 2019. Notice that the number that is added or subtracted is a product of two or three unique primes!
100 + 1919 ===> 1919 is a product of two prime numbers
400 + 1619 ===> 1619 is a prime number
900 + 1119 ===> 1119 is a product of two prime numbers again
1600 + 419 ===> 419 is a prime number
2500 - 381 ===> 381 is a product of two prime numbers
3600 - 1581 ===> 1581 is a product of three prime numbers
4900 - 2881 ===> 2881 is a product of two prime numbers
6400 - 4381 ===> 4381 is a product of two prime numbers
8100 - 6081 ===> 6081 is a product of two prime numbers again!
10000 - 7981 ===> 7981 is a product of two prime numbers!
Now if you look at 2019 - it is also a product of two unique primes! (673 and 3)
This is one prime reason why 2019 could be unique :)
