16503 has 4 divisors (see below), whose sum is σ = 22008. Its totient is φ = 11000.

The previous prime is 16493. The next prime is 16519. The reversal of 16503 is 30561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 16503 - 2⁴ = 16487 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between odd and even.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2748 + ... + 2753.

It is an arithmetic number, because the mean of its divisors is an integer number (5502).

2¹⁶⁵⁰³ is an apocalyptic number.

16503 is a deficient number, since it is larger than the sum of its proper divisors (5505).

16503 is an equidigital number, since it uses as much as digits as its factorization.

16503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5504.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 16503 is about 128.4640027401. The cubic root of 16503 is about 25.4597596770.

It can be divided in two parts, 1650 and 3, that multiplied together give a triangular number (4950 = T₉₉).

The spelling of 16503 in words is "sixteen thousand, five hundred three".