11011212211221 has 24 divisors (see below), whose sum is σ = 16335387106584. Its totient is φ = 7142217431040.

The previous prime is 11011212211211. The next prime is 11011212211231. The reversal of 11011212211221 is 12211221211011.

It is a happy number.

11011212211221 is a `hidden beast` number, since 1 + 10 + 11 + 212 + 211 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (11011212211211) and next prime (11011212211231).

It can be written as a sum of positive squares in 4 ways, for example, as 2279009910321 + 8732202300900 = 1509639^2 + 2955030^2 .

It is not a de Polignac number, because 11011212211221 - 2¹⁸ = 11011211949077 is a prime.

11011212211221 is a modest number, since divided by 12211221 gives 110112 as remainder.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 11011212211194 and 11011212211203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11011212211201) 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, 12645925 + ... + 13488581.

It is an arithmetic number, because the mean of its divisors is an integer number (680641129441).

Almost surely, 2^{11011212211221} is an apocalyptic number.

It is an amenable number.

11011212211221 is a deficient number, since it is larger than the sum of its proper divisors (5324174895363).

11011212211221 is a wasteful number, since it uses less digits than its factorization.

11011212211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 881941 (or 881938 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 11011212211221 its reverse (12211221211011), we get a palindrome (23222433422232).

The spelling of 11011212211221 in words is "eleven trillion, eleven billion, two hundred twelve million, two hundred eleven thousand, two hundred twenty-one".