540 can be written using four 4's:
See also 113
540 has 24
divisors (see below), whose sum is σ = 1680
Its totient is φ = 144
The previous prime is 523. The next prime is 541. The reversal of 540 is 45.
540 = T5 + T6 + ... +
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a nialpdrome in base 9 and base 10.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (541) by changing a digit.
540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106 + ... + 110.
It is an arithmetic number, because the mean of its divisors is an integer number (70).
2540 is an apocalyptic number.
540 is the 15-th heptagonal number and also the 12-th decagonal number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (840).
540 is an abundant number, since it is smaller than the sum of its proper divisors (1140).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
540 is a wasteful number, since it uses less digits than its factorization.
540 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 18 (or 10 counting only the distinct ones).
The product of its (nonzero) digits is 20, while the sum is 9.
The square root of 540 is about 23.2379000772.
The cubic root of 540 is about 8.1432528498.
540 divided by its product of nonzero digits (20) gives a cube (27 = 33).
Adding to 540 its reverse (45), we get a palindrome (585).
It can be divided in two parts, 5 and 40, that added together give a triangular number (45 = T9).
The spelling of 540 in words is "five hundred forty", and thus it is an aban number.