2020

This number is a composite.

+ The dystopian future-fiction novel Nineteen Eighty-Four was submitted for publication in December of 1948. The full span is p12 years, while with emirp partner p21 the span would instead be through 2020. [Merickel]

+ (2020)47120 * 2^20202 - 1 is prime. [Noll]

+ For three composite years y-1, y, and y+1 the prime factorization of y has no digits in common with the prime factorizations of y-1 or y+1 for y=2020. The last three years with this property were 1815, 1935, and 2019. The next three such years will be 2045, 2049, and 2065. [Gaydos]

+ Our current calendar year, 2020, may be computed with the same "formula" by using any of the one-digit primes (2, 3, 5 and 7), one at a time, as shown: 2020 = {[(dddd-dd)*dd]/(d+d)+dd-d}/(d+d+d) = {[(2222-22)*22]/(2+2)+22-2}/(2+2+2) = {[(3333-33)*33]/(3+3)+33-3}/(3+3+3) = {[(5555-55)*55]/(5+5)+55-5}/(5+5+5) = {[(7777-77)*77]/(7+7)+77-7}/(7+7+7). [Rivera]

(There is one curio for this number that has not yet been approved by an editor.)

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