20121221121 has 16 divisors (see below), whose sum is σ = 26875776000. Its totient is φ = 13390432128.

The previous prime is 20121221117. The next prime is 20121221129. The reversal of 20121221121 is 12112212102.

It is not a de Polignac number, because 20121221121 - 2² = 20121221117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121221121.

It is not an unprimeable number, because it can be changed into a prime (20121221129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5832205 + ... + 5835653.

It is an arithmetic number, because the mean of its divisors is an integer number (1679736000).

Almost surely, 2^20121221121 is an apocalyptic number.

It is an amenable number.

20121221121 is a deficient number, since it is larger than the sum of its proper divisors (6754554879).

20121221121 is a wasteful number, since it uses less digits than its factorization.

20121221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6328.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 20121221121 its reverse (12112212102), we get a palindrome (32233433223).

The spelling of 20121221121 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, one hundred twenty-one".