18871890443 has 4 divisors (see below), whose sum is σ = 21567874800. Its totient is φ = 16175906088.

The previous prime is 18871890437. The next prime is 18871890461. The reversal of 18871890443 is 34409817881.

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: 34409817881 = 107 ⋅321587083.

It is a cyclic number.

It is not a de Polignac number, because 18871890443 - 2⁸ = 18871890187 is a prime.

It is a super-2 number, since 2×18871890443² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18871890413) 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, 1347992168 + ... + 1347992181.

It is an arithmetic number, because the mean of its divisors is an integer number (5391968700).

Almost surely, 2^18871890443 is an apocalyptic number.

18871890443 is a deficient number, since it is larger than the sum of its proper divisors (2695984357).

18871890443 is an equidigital number, since it uses as much as digits as its factorization.

18871890443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2695984356.

The product of its (nonzero) digits is 1548288, while the sum is 53.

The spelling of 18871890443 in words is "eighteen billion, eight hundred seventy-one million, eight hundred ninety thousand, four hundred forty-three".