11111221211 has 4 divisors (see below), whose sum is σ = 11494366800. Its totient is φ = 10728075624.

The previous prime is 11111221201. The next prime is 11111221213. The reversal of 11111221211 is 11212211111.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11212211111 = 149 ⋅75249739.

It is a cyclic number.

It is not a de Polignac number, because 11111221211 - 2¹⁴ = 11111204827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11111221213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 191572751 + ... + 191572808.

It is an arithmetic number, because the mean of its divisors is an integer number (2873591700).

Almost surely, 2^11111221211 is an apocalyptic number.

11111221211 is a deficient number, since it is larger than the sum of its proper divisors (383145589).

11111221211 is an equidigital number, since it uses as much as digits as its factorization.

11111221211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383145588.

The product of its digits is 8, while the sum is 14.

Adding to 11111221211 its reverse (11212211111), we get a palindrome (22323432322).

The spelling of 11111221211 in words is "eleven billion, one hundred eleven million, two hundred twenty-one thousand, two hundred eleven".