21112012220021 has 4 divisors (see below), whose sum is σ = 21123320209152. Its totient is φ = 21100704230892.

The previous prime is 21112012220017. The next prime is 21112012220111. The reversal of 21112012220021 is 12002221021112.

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 21112012220021 - 2² = 21112012220017 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 (21112012223021) 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, 5653991765 + ... + 5653995498.

It is an arithmetic number, because the mean of its divisors is an integer number (5280830052288).

Almost surely, 2^{21112012220021} is an apocalyptic number.

It is an amenable number.

21112012220021 is a deficient number, since it is larger than the sum of its proper divisors (11307989131).

21112012220021 is a wasteful number, since it uses less digits than its factorization.

21112012220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11307989130.

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

Adding to 21112012220021 its reverse (12002221021112), we get a palindrome (33114233241133).

The spelling of 21112012220021 in words is "twenty-one trillion, one hundred twelve billion, twelve million, two hundred twenty thousand, twenty-one".