20021111111021 has 4 divisors (see below), whose sum is σ = 20023586834592. Its totient is φ = 20018635387452.

The previous prime is 20021111111017. The next prime is 20021111111047. The reversal of 20021111111021 is 12011111112002.

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 a cyclic number.

It is not a de Polignac number, because 20021111111021 - 2² = 20021111111017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20021111110987 and 20021111111005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021111111081) 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, 1237849655 + ... + 1237865828.

It is an arithmetic number, because the mean of its divisors is an integer number (5005896708648).

Almost surely, 2^{20021111111021} is an apocalyptic number.

It is an amenable number.

20021111111021 is a deficient number, since it is larger than the sum of its proper divisors (2475723571).

20021111111021 is an equidigital number, since it uses as much as digits as its factorization.

20021111111021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2475723570.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 20021111111021 its reverse (12011111112002), we get a palindrome (32032222223023).

The spelling of 20021111111021 in words is "twenty trillion, twenty-one billion, one hundred eleven million, one hundred eleven thousand, twenty-one".