Happy new year! Interesting numerical properties of 2021: a thread👇
2021 = 4347 is semi-prime, meaning it's the product of two primes – and that's not all: it's a product of "cousin primes" that differ by only 4. The last such year was 1517, and the next is 4757.
Even the next product of consecutive primes is a long way off – that's 2491.