21220121122121 has 8 divisors (see below), whose sum is σ = 21239466399360. Its totient is φ = 21200778318928.

The previous prime is 21220121122093. The next prime is 21220121122127. The reversal of 21220121122121 is 12122112102212.

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

It is a cyclic number.

It is not a de Polignac number, because 21220121122121 - 2¹⁰ = 21220121121097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21220121122093 and 21220121122102.

It is not an unprimeable number, because it can be changed into a prime (21220121122127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16765895 + ... + 17987091.

It is an arithmetic number, because the mean of its divisors is an integer number (2654933299920).

Almost surely, 2^{21220121122121} is an apocalyptic number.

It is an amenable number.

21220121122121 is a deficient number, since it is larger than the sum of its proper divisors (19345277239).

21220121122121 is a wasteful number, since it uses less digits than its factorization.

21220121122121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1237023.

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

Adding to 21220121122121 its reverse (12122112102212), we get a palindrome (33342233224333).

The spelling of 21220121122121 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, one hundred twenty-two thousand, one hundred twenty-one".