20493 has 20 divisors (see below), whose sum is σ = 34848. Its totient is φ = 11880.

The previous prime is 20483. The next prime is 20507. The reversal of 20493 is 39402.

It is not a de Polignac number, because 20493 - 2⁴ = 20477 is a prime.

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 880 + ... + 902.

2²⁰⁴⁹³ is an apocalyptic number.

20493 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20493 is a deficient number, since it is larger than the sum of its proper divisors (14355).

20493 is a wasteful number, since it uses less digits than its factorization.

20493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46 (or 37 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 20493 is about 143.1537634853. The cubic root of 20493 is about 27.3654029034.

Adding to 20493 its reverse (39402), we get a palindrome (59895).

The spelling of 20493 in words is "twenty thousand, four hundred ninety-three".