11111101221 has 32 divisors (see below), whose sum is σ = 16660598400. Its totient is φ = 6527450880.

The previous prime is 11111101217. The next prime is 11111101241. The reversal of 11111101221 is 12210111111.

11111101221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11111101221 - 2² = 11111101217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 11111101197 and 11111101206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111101241) 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 in 31 ways as a sum of consecutive naturals, for example, 311535 + ... + 345363.

It is an arithmetic number, because the mean of its divisors is an integer number (520643700).

Almost surely, 2^11111101221 is an apocalyptic number.

11111101221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11111101221 is a deficient number, since it is larger than the sum of its proper divisors (5549497179).

11111101221 is a wasteful number, since it uses less digits than its factorization.

11111101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34149.

The product of its (nonzero) digits is 4, while the sum is 12.

Adding to 11111101221 its reverse (12210111111), we get a palindrome (23321212332).

The spelling of 11111101221 in words is "eleven billion, one hundred eleven million, one hundred one thousand, two hundred twenty-one".