20210220021 has 4 divisors (see below), whose sum is σ = 26946960032. Its totient is φ = 13473480012.

The previous prime is 20210219993. The next prime is 20210220097. The reversal of 20210220021 is 12002201202.

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.

It is not a de Polignac number, because 20210220021 - 2⁵ = 20210219989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20210219979 and 20210220006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20210220521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3368370001 + ... + 3368370006.

It is an arithmetic number, because the mean of its divisors is an integer number (6736740008).

Almost surely, 2^20210220021 is an apocalyptic number.

It is an amenable number.

20210220021 is a deficient number, since it is larger than the sum of its proper divisors (6736740011).

20210220021 is an equidigital number, since it uses as much as digits as its factorization.

20210220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6736740010.

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 20210220021 its reverse (12002201202), we get a palindrome (32212421223).

The spelling of 20210220021 in words is "twenty billion, two hundred ten million, two hundred twenty thousand, twenty-one".