Subtracting 20503 from its reverse (30502), we obtain a palindrome (9999).
It is a sphenic number, since it is the product of 3 distinct primes.
It is a Duffinian number.
It is a plaindrome in base 11.
It is a nialpdrome in base 9 and base 13.
It is a self number, because there is not a number n which added to its sum of digits gives 20503.
It is a congruent number.
220503 is an apocalyptic number.
20503 is the 202-nd triangular number.
20503 is the 68-th centered nonagonal number.
20503 is a wasteful number, since it uses less digits than its factorization.
20503 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 137.
The square root of 20503 is about 143.1886867039. The cubic root of 20503 is about 27.3698533585.
The spelling of 20503 in words is "twenty thousand, five hundred three".