2021 = 43 x 47 (the product of two consecutive prime numbers: A006094). As the product of two primes, 2021 is a semiprime.
2021 = 452 − 4 (A028347).
The Euler polynomial x2 + x + 41 generates an unbroken sequence of 40 primes, starting with x = 0. 2021 is the third composite number that the formula produces (for x = 44) (A145292).
2021 is the sum of the first 24 pairs of consecutive primes (A102724).
The sum of the divisors of 2021 (1, 43, 47, 2021) is palindromic: 2112.
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