66540 has 24 divisors (see below), whose sum is σ = 186480. Its totient is φ = 17728.

The previous prime is 66533. The next prime is 66541. The reversal of 66540 is 4566.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 66540.

It is not an unprimeable number, because it can be changed into a prime (66541) 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, 495 + ... + 614.

It is an arithmetic number, because the mean of its divisors is an integer number (7770).

2⁶⁶⁵⁴⁰ is an apocalyptic number.

66540 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66540 is an abundant number, since it is smaller than the sum of its proper divisors (119940).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (93240).

66540 is a wasteful number, since it uses less digits than its factorization.

66540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121 (or 1119 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 66540 is about 257.9534841788. The cubic root of 66540 is about 40.5223166139.

It can be divided in two parts, 66 and 540, that added together give a palindrome (606).

The spelling of 66540 in words is "sixty-six thousand, five hundred forty".