216540216 has 192 divisors, whose sum is σ = 660441600. Its totient is φ = 66261888.

The previous prime is 216540211. The next prime is 216540221. The reversal of 216540216 is 612045612.

216540216 is a `hidden beast` number, since 2 + 1 + 654 + 0 + 2 + 1 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (216540211) and next prime (216540221).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 216540216.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216540211) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 1296565 + ... + 1296731.

It is an arithmetic number, because the mean of its divisors is an integer number (3439800).

Almost surely, 2^216540216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216540216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (330220800).

216540216 is an abundant number, since it is smaller than the sum of its proper divisors (443901384).

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

216540216 is a wasteful number, since it uses less digits than its factorization.

216540216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 216540216 is about 14715.3055014159. The cubic root of 216540216 is about 600.4997835784.

Adding to 216540216 its reverse (612045612), we get a palindrome (828585828).

The spelling of 216540216 in words is "two hundred sixteen million, five hundred forty thousand, two hundred sixteen".