2021020021 has 2 divisors, whose sum is σ = 2021020022. Its totient is φ = 2021020020.

The previous prime is 2021020007. The next prime is 2021020033. The reversal of 2021020021 is 1200201202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1609132996 + 411887025 = 40114^2 + 20295^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021020021 - 2⁹ = 2021019509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2021020091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010510010 + 1010510011.

It is an arithmetic number, because the mean of its divisors is an integer number (1010510011).

Almost surely, 2^2021020021 is an apocalyptic number.

It is an amenable number.

2021020021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021020021 is an equidigital number, since it uses as much as digits as its factorization.

2021020021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 2021020021 is about 44955.7562610173. The cubic root of 2021020021 is about 1264.3196039020.

Adding to 2021020021 its reverse (1200201202), we get a palindrome (3221221223).

The spelling of 2021020021 in words is "two billion, twenty-one million, twenty thousand, twenty-one".