11211110121221 has 16 divisors (see below), whose sum is σ = 11260264277808. Its totient is φ = 11162065305600.

The previous prime is 11211110121217. The next prime is 11211110121223. The reversal of 11211110121221 is 12212101111211.

It can be written as a sum of positive squares in 8 ways, for example, as 296273376100 + 10914836745121 = 544310^2 + 3303761^2 .

It is a cyclic number.

It is not a de Polignac number, because 11211110121221 - 2² = 11211110121217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11211110121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11211110121223) 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, 951943685 + ... + 951955461.

It is an arithmetic number, because the mean of its divisors is an integer number (703766517363).

Almost surely, 2^{11211110121221} is an apocalyptic number.

It is an amenable number.

11211110121221 is a deficient number, since it is larger than the sum of its proper divisors (49154156587).

11211110121221 is a wasteful number, since it uses less digits than its factorization.

11211110121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16072.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 11211110121221 its reverse (12212101111211), we get a palindrome (23423211232432).

The spelling of 11211110121221 in words is "eleven trillion, two hundred eleven billion, one hundred ten million, one hundred twenty-one thousand, two hundred twenty-one".