11111221191 has 16 divisors (see below), whose sum is σ = 17099025408. Its totient is φ = 6286404000.

The previous prime is 11111221139. The next prime is 11111221193. The reversal of 11111221191 is 19112211111.

It is a happy number.

It is not a de Polignac number, because 11111221191 - 2⁶ = 11111221127 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111221193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2617215 + ... + 2621456.

It is an arithmetic number, because the mean of its divisors is an integer number (1068689088).

Almost surely, 2^11111221191 is an apocalyptic number.

11111221191 is a deficient number, since it is larger than the sum of its proper divisors (5987804217).

11111221191 is a wasteful number, since it uses less digits than its factorization.

11111221191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5238782.

The product of its digits is 36, while the sum is 21.

The spelling of 11111221191 in words is "eleven billion, one hundred eleven million, two hundred twenty-one thousand, one hundred ninety-one".