18711889 has 4 divisors (see below), whose sum is σ = 21385024. Its totient is φ = 16038756.

The previous prime is 18711851. The next prime is 18711919. The reversal of 18711889 is 98811781.

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, and also an emirpimes, since its reverse is a distinct semiprime: 98811781 = 647 ⋅152723.

It is a cyclic number.

It is not a de Polignac number, because 18711889 - 2⁹ = 18711377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18711829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1336557 + ... + 1336570.

It is an arithmetic number, because the mean of its divisors is an integer number (5346256).

Almost surely, 2^18711889 is an apocalyptic number.

It is an amenable number.

18711889 is a deficient number, since it is larger than the sum of its proper divisors (2673135).

18711889 is an equidigital number, since it uses as much as digits as its factorization.

18711889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2673134.

The product of its digits is 32256, while the sum is 43.

The square root of 18711889 is about 4325.7241012344. The cubic root of 18711889 is about 265.4845247357.

It can be divided in two parts, 18711 and 889, that added together give a square (19600 = 140²).

The spelling of 18711889 in words is "eighteen million, seven hundred eleven thousand, eight hundred eighty-nine".