216540 has 48 divisors (see below), whose sum is σ = 675360. Its totient is φ = 57600.

The previous prime is 216523. The next prime is 216551. The reversal of 216540 is 45612.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

216540 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 340 + ... + 740.

It is an arithmetic number, because the mean of its divisors is an integer number (14070).

2²¹⁶⁵⁴⁰ is an apocalyptic number.

216540 is a gapful number since it is divisible by the number (20) 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 216540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (337680).

216540 is an abundant number, since it is smaller than the sum of its proper divisors (458820).

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

216540 is a wasteful number, since it uses less digits than its factorization.

216540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419 (or 411 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 216540 is about 465.3385864078. The cubic root of 216540 is about 60.0499583911.

It can be divided in two parts, 21 and 6540, that added together give a 8-th power (6561 = 3⁸).

The spelling of 216540 in words is "two hundred sixteen thousand, five hundred forty".