11101211121221 has 16 divisors (see below), whose sum is σ = 12157296935280. Its totient is φ = 10074173713920.

The previous prime is 11101211121193. The next prime is 11101211121233. The reversal of 11101211121221 is 12212111210111.

It can be written as a sum of positive squares in 8 ways, for example, as 8228372568196 + 2872838553025 = 2868514^2 + 1694945^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11101211121221 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 11101211121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11101211121251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1983056 + ... + 5112233.

It is an arithmetic number, because the mean of its divisors is an integer number (759831058455).

Almost surely, 2^{11101211121221} is an apocalyptic number.

It is an amenable number.

11101211121221 is a deficient number, since it is larger than the sum of its proper divisors (1056085814059).

11101211121221 is a wasteful number, since it uses less digits than its factorization.

11101211121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7097336.

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

Adding to 11101211121221 its reverse (12212111210111), we get a palindrome (23313322331332).

The spelling of 11101211121221 in words is "eleven trillion, one hundred one billion, two hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".