20201021021 has 2 divisors, whose sum is σ = 20201021022. Its totient is φ = 20201021020.

The previous prime is 20201020969. The next prime is 20201021039. The reversal of 20201021021 is 12012010202.

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., 17659752100 + 2541268921 = 132890^2 + 50411^2 .

It is a cyclic number.

It is not a de Polignac number, because 20201021021 - 2¹⁰ = 20201019997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20201020993 and 20201021011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20201021221) 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, 10100510510 + 10100510511.

It is an arithmetic number, because the mean of its divisors is an integer number (10100510511).

Almost surely, 2^20201021021 is an apocalyptic number.

It is an amenable number.

20201021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20201021021 is an equidigital number, since it uses as much as digits as its factorization.

20201021021 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 11.

Adding to 20201021021 its reverse (12012010202), we get a palindrome (32213031223).

The spelling of 20201021021 in words is "twenty billion, two hundred one million, twenty-one thousand, twenty-one".