20211020111021 has 4 divisors (see below), whose sum is σ = 21089760115872. Its totient is φ = 19332280106172.

The previous prime is 20211020111011. The next prime is 20211020111057. The reversal of 20211020111021 is 12011102011202.

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 20211020111021 - 2²² = 20211015916717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20211020110987 and 20211020111005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211020111011) 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, 439370002391 + ... + 439370002436.

It is an arithmetic number, because the mean of its divisors is an integer number (5272440028968).

Almost surely, 2^{20211020111021} is an apocalyptic number.

It is an amenable number.

20211020111021 is a deficient number, since it is larger than the sum of its proper divisors (878740004851).

20211020111021 is an equidigital number, since it uses as much as digits as its factorization.

20211020111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878740004850.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 20211020111021 its reverse (12011102011202), we get a palindrome (32222122122223).

The spelling of 20211020111021 in words is "twenty trillion, two hundred eleven billion, twenty million, one hundred eleven thousand, twenty-one".