18489563821 has 4 divisors (see below), whose sum is σ = 18571015872. Its totient is φ = 18408111772.

The previous prime is 18489563797. The next prime is 18489563831. The reversal of 18489563821 is 12836598481.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18489563821 - 2⁵ = 18489563789 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 (18489563831) 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, 40725685 + ... + 40726138.

It is an arithmetic number, because the mean of its divisors is an integer number (4642753968).

Almost surely, 2^18489563821 is an apocalyptic number.

It is an amenable number.

18489563821 is a deficient number, since it is larger than the sum of its proper divisors (81452051).

18489563821 is an equidigital number, since it uses as much as digits as its factorization.

18489563821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81452050.

The product of its digits is 3317760, while the sum is 55.

The spelling of 18489563821 in words is "eighteen billion, four hundred eighty-nine million, five hundred sixty-three thousand, eight hundred twenty-one".