20211111021 has 4 divisors (see below), whose sum is σ = 26948148032. Its totient is φ = 13474074012.

The previous prime is 20211110929. The next prime is 20211111023. The reversal of 20211111021 is 12011111202.

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 20211111021 - 2¹⁵ = 20211078253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20211110988 and 20211111006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211111023) 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 in 3 ways as a sum of consecutive naturals, for example, 3368518501 + ... + 3368518506.

It is an arithmetic number, because the mean of its divisors is an integer number (6737037008).

Almost surely, 2^20211111021 is an apocalyptic number.

It is an amenable number.

20211111021 is a deficient number, since it is larger than the sum of its proper divisors (6737037011).

20211111021 is an equidigital number, since it uses as much as digits as its factorization.

20211111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6737037010.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 20211111021 its reverse (12011111202), we get a palindrome (32222222223).

The spelling of 20211111021 in words is "twenty billion, two hundred eleven million, one hundred eleven thousand, twenty-one".