20212221121 has 6 divisors (see below), whose sum is σ = 20560611122. Its totient is φ = 19869637680.

The previous prime is 20212221103. The next prime is 20212221137. The reversal of 20212221121 is 12112221202.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20117450896 + 94770225 = 141836^2 + 9735^2 .

It is not a de Polignac number, because 20212221121 - 2²⁹ = 19675350209 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20212221095 and 20212221104.

It is not an unprimeable number, because it can be changed into a prime (20212821121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2899740 + ... + 2906701.

Almost surely, 2^20212221121 is an apocalyptic number.

It is an amenable number.

20212221121 is a deficient number, since it is larger than the sum of its proper divisors (348390001).

20212221121 is an frugal number, since it uses more digits than its factorization.

20212221121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5806559 (or 5806500 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 20212221121 its reverse (12112221202), we get a palindrome (32324442323).

The spelling of 20212221121 in words is "twenty billion, two hundred twelve million, two hundred twenty-one thousand, one hundred twenty-one".