2021021021 has 2 divisors, whose sum is σ = 2021021022. Its totient is φ = 2021021020.

The previous prime is 2021020973. The next prime is 2021021039. The reversal of 2021021021 is 1201201202.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1205061796 + 815959225 = 34714^2 + 28565^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021021021 - 2⁶ = 2021020957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2021020993 and 2021021011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2021021071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1010510510 + 1010510511.

It is an arithmetic number, because the mean of its divisors is an integer number (1010510511).

Almost surely, 2^2021021021 is an apocalyptic number.

It is an amenable number.

2021021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2021021021 is an equidigital number, since it uses as much as digits as its factorization.

2021021021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 2021021021 is about 44955.7673830622. The cubic root of 2021021021 is about 1264.3198124302.

Adding to 2021021021 its reverse (1201201202), we get a palindrome (3222222223).

The spelling of 2021021021 in words is "two billion, twenty-one million, twenty-one thousand, twenty-one".