18421028891 has 4 divisors (see below), whose sum is σ = 18421409400. Its totient is φ = 18420648384.

The previous prime is 18421028869. The next prime is 18421028893. The reversal of 18421028891 is 19882012481.

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 18421028891 - 2¹⁸ = 18420766747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18421028893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104861 + ... + 218718.

It is an arithmetic number, because the mean of its divisors is an integer number (4605352350).

Almost surely, 2^18421028891 is an apocalyptic number.

18421028891 is a deficient number, since it is larger than the sum of its proper divisors (380509).

18421028891 is an equidigital number, since it uses as much as digits as its factorization.

18421028891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380508.

The product of its (nonzero) digits is 73728, while the sum is 44.

The spelling of 18421028891 in words is "eighteen billion, four hundred twenty-one million, twenty-eight thousand, eight hundred ninety-one".