18711989 has 8 divisors (see below), whose sum is σ = 19407360. Its totient is φ = 18020016.

The previous prime is 18711977. The next prime is 18711991. The reversal of 18711989 is 98911781.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18711989 - 2⁸ = 18711733 is a prime.

It is a super-2 number, since 2×18711989² = 700277064672242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18711919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17072 + ... + 18134.

It is an arithmetic number, because the mean of its divisors is an integer number (2425920).

Almost surely, 2^18711989 is an apocalyptic number.

It is an amenable number.

18711989 is a deficient number, since it is larger than the sum of its proper divisors (695371).

18711989 is a wasteful number, since it uses less digits than its factorization.

18711989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1699.

The product of its digits is 36288, while the sum is 44.

The square root of 18711989 is about 4325.7356599774. The cubic root of 18711989 is about 265.4849976686.

The spelling of 18711989 in words is "eighteen million, seven hundred eleven thousand, nine hundred eighty-nine".