20110121211221 has 2 divisors, whose sum is σ = 20110121211222. Its totient is φ = 20110121211220.

The previous prime is 20110121211217. The next prime is 20110121211233. The reversal of 20110121211221 is 12211212101102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11819672100625 + 8290449110596 = 3437975^2 + 2879314^2 .

It is a cyclic number.

It is not a de Polignac number, because 20110121211221 - 2² = 20110121211217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20110121211221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20110121211251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10055060605610 + 10055060605611.

It is an arithmetic number, because the mean of its divisors is an integer number (10055060605611).

Almost surely, 2^{20110121211221} is an apocalyptic number.

It is an amenable number.

20110121211221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20110121211221 is an equidigital number, since it uses as much as digits as its factorization.

20110121211221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 20110121211221 its reverse (12211212101102), we get a palindrome (32321333312323).

The spelling of 20110121211221 in words is "twenty trillion, one hundred ten billion, one hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".