21012220112021 has 4 divisors (see below), whose sum is σ = 21016464152544. Its totient is φ = 21007976071500.

The previous prime is 21012220111999. The next prime is 21012220112033. The reversal of 21012220112021 is 12021102221012.

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 21012220112021 - 2²⁶ = 21012153003157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012220112041) 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, 2122012835 + ... + 2122022736.

It is an arithmetic number, because the mean of its divisors is an integer number (5254116038136).

Almost surely, 2^{21012220112021} is an apocalyptic number.

It is an amenable number.

21012220112021 is a deficient number, since it is larger than the sum of its proper divisors (4244040523).

21012220112021 is an equidigital number, since it uses as much as digits as its factorization.

21012220112021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4244040522.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21012220112021 its reverse (12021102221012), we get a palindrome (33033322333033).

The spelling of 21012220112021 in words is "twenty-one trillion, twelve billion, two hundred twenty million, one hundred twelve thousand, twenty-one".