19889 has 2 divisors, whose sum is σ = 19890. Its totient is φ = 19888.

The previous prime is 19867. The next prime is 19891. The reversal of 19889 is 98891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19600 + 289 = 140^2 + 17^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19889 is a prime.

It is a Sophie Germain prime.

Together with 19891, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19819) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9944 + 9945.

It is an arithmetic number, because the mean of its divisors is an integer number (9945).

2¹⁹⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

19889 is a deficient number, since it is larger than the sum of its proper divisors (1).

19889 is an equidigital number, since it uses as much as digits as its factorization.

19889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 35.

The square root of 19889 is about 141.0283659410. The cubic root of 19889 is about 27.0938662516.

The spelling of 19889 in words is "nineteen thousand, eight hundred eighty-nine".