11111323221 has 24 divisors (see below), whose sum is σ = 16494037560. Its totient is φ = 7202722176.

The previous prime is 11111323217. The next prime is 11111323231. The reversal of 11111323221 is 12232311111.

11111323221 is a `hidden beast` number, since 11 + 111 + 323 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3192815025 + 7918508196 = 56505^2 + 88986^2 .

It is not a de Polignac number, because 11111323221 - 2² = 11111323217 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 11111323194 and 11111323203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111323231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 553915 + ... + 573623.

It is an arithmetic number, because the mean of its divisors is an integer number (687251565).

Almost surely, 2^11111323221 is an apocalyptic number.

It is an amenable number.

11111323221 is a deficient number, since it is larger than the sum of its proper divisors (5382714339).

11111323221 is a wasteful number, since it uses less digits than its factorization.

11111323221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21445 (or 21442 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 11111323221 its reverse (12232311111), we get a palindrome (23343634332).

The spelling of 11111323221 in words is "eleven billion, one hundred eleven million, three hundred twenty-three thousand, two hundred twenty-one".