11111221291 has 4 divisors (see below), whose sum is σ = 11112294312. Its totient is φ = 11110148272.

The previous prime is 11111221279. The next prime is 11111221307. The reversal of 11111221291 is 19212211111.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19212211111 = 72043 ⋅266677.

It is a cyclic number.

It is not a de Polignac number, because 11111221291 - 2⁵ = 11111221259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11111221201) 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, 520825 + ... + 541738.

It is an arithmetic number, because the mean of its divisors is an integer number (2778073578).

Almost surely, 2^11111221291 is an apocalyptic number.

11111221291 is a deficient number, since it is larger than the sum of its proper divisors (1073021).

11111221291 is a wasteful number, since it uses less digits than its factorization.

11111221291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1073020.

The product of its digits is 72, while the sum is 22.

The spelling of 11111221291 in words is "eleven billion, one hundred eleven million, two hundred twenty-one thousand, two hundred ninety-one".