18001112021 has 2 divisors, whose sum is σ = 18001112022. Its totient is φ = 18001112020.

The previous prime is 18001112011. The next prime is 18001112027. The reversal of 18001112021 is 12021110081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17979859921 + 21252100 = 134089^2 + 4610^2 .

It is an emirp because it is prime and its reverse (12021110081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18001112021 - 2³⁰ = 16927370197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18001112027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9000556010 + 9000556011.

It is an arithmetic number, because the mean of its divisors is an integer number (9000556011).

Almost surely, 2^18001112021 is an apocalyptic number.

It is an amenable number.

18001112021 is a deficient number, since it is larger than the sum of its proper divisors (1).

18001112021 is an equidigital number, since it uses as much as digits as its factorization.

18001112021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 17.

The spelling of 18001112021 in words is "eighteen billion, one million, one hundred twelve thousand, twenty-one".