21201121222121 has 8 divisors (see below), whose sum is σ = 21745946634720. Its totient is φ = 20658649267872.

The previous prime is 21201121222111. The next prime is 21201121222181. The reversal of 21201121222121 is 12122212110212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-21201121222121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201121222093 and 21201121222102.

It is not an unprimeable number, because it can be changed into a prime (21201121222111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 588346340 + ... + 588382373.

It is an arithmetic number, because the mean of its divisors is an integer number (2718243329340).

Almost surely, 2^{21201121222121} is an apocalyptic number.

It is an amenable number.

21201121222121 is a deficient number, since it is larger than the sum of its proper divisors (544825412599).

21201121222121 is a wasteful number, since it uses less digits than its factorization.

21201121222121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176729175.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21201121222121 its reverse (12122212110212), we get a palindrome (33323333332333).

The spelling of 21201121222121 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-one million, two hundred twenty-two thousand, one hundred twenty-one".