Adding to 2021 its reverse (1202), we get a palindrome (3223).
Multipling 2021 by its reverse (1202), we get a palindrome (2429242).
It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1202 = 2 ⋅601.
It is a cyclic number.
It is a Duffinian number.
It is a plaindrome in base 11.
It is a congruent number.
22021 is an apocalyptic number.
It is an amenable number.
2021 is an equidigital number, since it uses as much as digits as its factorization.
2021 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 90.
The square root of 2021 is about 44.9555335860. The cubic root of 2021 is about 12.6431542894.
The spelling of 2021 in words is "two thousand, twenty-one", and thus it is an iban number.