20121121221 has 4 divisors (see below), whose sum is σ = 26828161632. Its totient is φ = 13414080812.

The previous prime is 20121121213. The next prime is 20121121247. The reversal of 20121121221 is 12212112102.

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 20121121221 - 2³ = 20121121213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121121271) 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, 3353520201 + ... + 3353520206.

It is an arithmetic number, because the mean of its divisors is an integer number (6707040408).

Almost surely, 2^20121121221 is an apocalyptic number.

It is an amenable number.

20121121221 is a deficient number, since it is larger than the sum of its proper divisors (6707040411).

20121121221 is an equidigital number, since it uses as much as digits as its factorization.

20121121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6707040410.

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

Adding to 20121121221 its reverse (12212112102), we get a palindrome (32333233323).

The spelling of 20121121221 in words is "twenty billion, one hundred twenty-one million, one hundred twenty-one thousand, two hundred twenty-one".