18001222111 has 4 divisors (see below), whose sum is σ = 18105275592. Its totient is φ = 17897168632.

The previous prime is 18001222103. The next prime is 18001222207. The reversal of 18001222111 is 11122210081.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18001222111 - 2³ = 18001222103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18601222111) 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, 52026481 + ... + 52026826.

It is an arithmetic number, because the mean of its divisors is an integer number (4526318898).

Almost surely, 2^18001222111 is an apocalyptic number.

18001222111 is a deficient number, since it is larger than the sum of its proper divisors (104053481).

18001222111 is a wasteful number, since it uses less digits than its factorization.

18001222111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104053480.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 18001222111 its reverse (11122210081), we get a palindrome (29123432192).

The spelling of 18001222111 in words is "eighteen billion, one million, two hundred twenty-two thousand, one hundred eleven".