6543 has 6 divisors (see below), whose sum is σ = 9464. Its totient is φ = 4356.

The previous prime is 6529. The next prime is 6547. The reversal of 6543 is 3456.

It is a happy number.

6543 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is not a de Polignac number, because 6543 - 2⁸ = 6287 is a prime.

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

It is a Duffinian number.

It is a straight-line number, since its digits are in arithmetic progression.

It is a plaindrome in base 14.

It is a nialpdrome in base 3, base 9 and base 10.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6547) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 355 + ... + 372.

2⁶⁵⁴³ is an apocalyptic number.

6543 is a deficient number, since it is larger than the sum of its proper divisors (2921).

6543 is a wasteful number, since it uses less digits than its factorization.

6543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733 (or 730 counting only the distinct ones).

The product of its digits is 360, while the sum is 18.

The square root of 6543 is about 80.8888125763. Note that the first 4 decimals coincide. The cubic root of 6543 is about 18.7036186959.

Adding to 6543 its sum of digits (18), we get a 8-th power (6561 = 3⁸).

Adding to 6543 its product of digits (360), we get a triangular number (6903 = T₁₁₇).

Adding to 6543 its reverse (3456), we get a palindrome (9999).

The spelling of 6543 in words is "six thousand, five hundred forty-three".