202021021 has 2 divisors, whose sum is σ = 202021022. Its totient is φ = 202021020.

The previous prime is 202020997. The next prime is 202021033. The reversal of 202021021 is 120120202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 185096025 + 16924996 = 13605^2 + 4114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-202021021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 202020989 and 202021007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (202021921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101010510 + 101010511.

It is an arithmetic number, because the mean of its divisors is an integer number (101010511).

Almost surely, 2^202021021 is an apocalyptic number.

It is an amenable number.

202021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

202021021 is an equidigital number, since it uses as much as digits as its factorization.

202021021 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 10.

The square root of 202021021 is about 14213.4099005130. The cubic root of 202021021 is about 586.7667832682.

Adding to 202021021 its reverse (120120202), we get a palindrome (322141223).

The spelling of 202021021 in words is "two hundred two million, twenty-one thousand, twenty-one".