20021110111021 has 4 divisors (see below), whose sum is σ = 20021126616252. Its totient is φ = 20021093605792.

The previous prime is 20021110111019. The next prime is 20021110111043. The reversal of 20021110111021 is 12011101112002.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13786450686121 + 6234659424900 = 3713011^2 + 2496930^2 .

It is a cyclic number.

It is not a de Polignac number, because 20021110111021 - 2¹ = 20021110111019 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021110110992 and 20021110111010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021110111421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6275146 + ... + 8911771.

It is an arithmetic number, because the mean of its divisors is an integer number (5005281654063).

Almost surely, 2^{20021110111021} is an apocalyptic number.

It is an amenable number.

20021110111021 is a deficient number, since it is larger than the sum of its proper divisors (16505231).

20021110111021 is a wasteful number, since it uses less digits than its factorization.

20021110111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16505230.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 20021110111021 its reverse (12011101112002), we get a palindrome (32032211223023).

The spelling of 20021110111021 in words is "twenty trillion, twenty-one billion, one hundred ten million, one hundred eleven thousand, twenty-one".