17989 has 2 divisors, whose sum is σ = 17990. Its totient is φ = 17988.

The previous prime is 17987. The next prime is 18013. The reversal of 17989 is 98971.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16900 + 1089 = 130^2 + 33^2 .

It is a cyclic number.

It is not a de Polignac number, because 17989 - 2¹ = 17987 is a prime.

Together with 17987, it forms a pair of twin primes.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (17981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8994 + 8995.

It is an arithmetic number, because the mean of its divisors is an integer number (8995).

2¹⁷⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

17989 is a deficient number, since it is larger than the sum of its proper divisors (1).

17989 is an equidigital number, since it uses as much as digits as its factorization.

17989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 34.

The square root of 17989 is about 134.1230778054. The cubic root of 17989 is about 26.2020743070.

Subtracting from 17989 its sum of digits (34), we obtain a triangular number (17955 = T₁₈₉).

It can be divided in two parts, 179 and 89, that multiplied together give a triangular number (15931 = T₁₇₈).

The spelling of 17989 in words is "seventeen thousand, nine hundred eighty-nine".