21121211121121 has 8 divisors (see below), whose sum is σ = 21628889222400. Its totient is φ = 20619541044960.

The previous prime is 21121211121107. The next prime is 21121211121133. The reversal of 21121211121121 is 12112111212112.

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 21121211121121 - 2²⁹ = 21120674250209 is a prime.

It is a super-2 number, since 2×21121211121121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121211121181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1501999165 + ... + 1502013226.

It is an arithmetic number, because the mean of its divisors is an integer number (2703611152800).

Almost surely, 2^{21121211121121} is an apocalyptic number.

It is an amenable number.

21121211121121 is a deficient number, since it is larger than the sum of its proper divisors (507678101279).

21121211121121 is an equidigital number, since it uses as much as digits as its factorization.

21121211121121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3004012559.

The product of its digits is 32, while the sum is 19.

Adding to 21121211121121 its reverse (12112111212112), we get a palindrome (33233322333233).

Subtracting from 21121211121121 its reverse (12112111212112), we obtain a palindrome (9009099909009).

The spelling of 21121211121121 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, one hundred twenty-one".