11111111323221 has 32 divisors (see below), whose sum is σ = 18726419100928. Its totient is φ = 5702405806080.

The previous prime is 11111111323217. The next prime is 11111111323229. The reversal of 11111111323221 is 12232311111111.

It is not a de Polignac number, because 11111111323221 - 2² = 11111111323217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111111323229) 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 31 ways as a sum of consecutive naturals, for example, 549990460 + ... + 550010661.

It is an arithmetic number, because the mean of its divisors is an integer number (585200596904).

Almost surely, 2^{11111111323221} is an apocalyptic number.

It is an amenable number.

11111111323221 is a deficient number, since it is larger than the sum of its proper divisors (7615307777707).

11111111323221 is a wasteful number, since it uses less digits than its factorization.

11111111323221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100001181.

The product of its digits is 72, while the sum is 21.

Adding to 11111111323221 its reverse (12232311111111), we get a palindrome (23343422434332).

The spelling of 11111111323221 in words is "eleven trillion, one hundred eleven billion, one hundred eleven million, three hundred twenty-three thousand, two hundred twenty-one".