6540 has 24 divisors (see below), whose sum is σ = 18480. Its totient is φ = 1728.

The previous prime is 6529. The next prime is 6547. The reversal of 6540 is 456.

6540 = 25² + 26² + ... + 32².

6540 is nontrivially palindromic in base 14.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a nialpdrome in base 9 and base 10.

It is a zygodrome in base 2 and base 9.

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 7 ways as a sum of consecutive naturals, for example, 6 + ... + 114.

It is an arithmetic number, because the mean of its divisors is an integer number (770).

2⁶⁵⁴⁰ is an apocalyptic number.

6540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9240).

6540 is an abundant number, since it is smaller than the sum of its proper divisors (11940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6540 is a wasteful number, since it uses less digits than its factorization.

6540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 6540 is about 80.8702664766. The cubic root of 6540 is about 18.7007596897.

Adding to 6540 its sum of digits (15), we get a triangular number (6555 = T₁₁₄).

Adding to 6540 its reverse (456), we get a palindrome (6996).

Subtracting from 6540 its reverse (456), we obtain a square (6084 = 78²).

It can be divided in two parts, 65 and 40, that added together give a triangular number (105 = T₁₄).

The spelling of 6540 in words is "six thousand, five hundred forty".