20489 has 4 divisors (see below), whose sum is σ = 23424. Its totient is φ = 17556.

The previous prime is 20483. The next prime is 20507. The reversal of 20489 is 98402.

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: 98402 = 2 ⋅49201.

It is not a de Polignac number, because 20489 - 2⁸ = 20233 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20489.

It is not an unprimeable number, because it can be changed into a prime (20483) 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, 1457 + ... + 1470.

It is an arithmetic number, because the mean of its divisors is an integer number (5856).

2²⁰⁴⁸⁹ is an apocalyptic number.

It is an amenable number.

20489 is a deficient number, since it is larger than the sum of its proper divisors (2935).

20489 is an equidigital number, since it uses as much as digits as its factorization.

20489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2934.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 20489 is about 143.1397918121. The cubic root of 20489 is about 27.3636223160.

The spelling of 20489 in words is "twenty thousand, four hundred eighty-nine".