216558 has 24 divisors (see below), whose sum is σ = 480168. Its totient is φ = 70512.

The previous prime is 216553. The next prime is 216569. The reversal of 216558 is 855612.

216558 is a `hidden beast` number, since 2 + 1 + 655 + 8 = 666.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a plaindrome in base 16.

It is a nialpdrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 216558.

It is not an unprimeable number, because it can be changed into a prime (216551) by changing a digit.

216558 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 11 ways as a sum of consecutive naturals, for example, 841 + ... + 1067.

It is an arithmetic number, because the mean of its divisors is an integer number (20007).

2²¹⁶⁵⁵⁸ is an apocalyptic number.

216558 is an abundant number, since it is smaller than the sum of its proper divisors (263610).

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

216558 is a wasteful number, since it uses less digits than its factorization.

216558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 285 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 216558 is about 465.3579267618. The cubic root of 216558 is about 60.0516222397.

The spelling of 216558 in words is "two hundred sixteen thousand, five hundred fifty-eight".