216506 has 8 divisors (see below), whose sum is σ = 328224. Its totient is φ = 107100.

The previous prime is 216493. The next prime is 216509. The reversal of 216506 is 605612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (216509) 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 3 ways as a sum of consecutive naturals, for example, 320 + ... + 731.

It is an arithmetic number, because the mean of its divisors is an integer number (41028).

2²¹⁶⁵⁰⁶ is an apocalyptic number.

216506 is a deficient number, since it is larger than the sum of its proper divisors (111718).

216506 is a wasteful number, since it uses less digits than its factorization.

216506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1156.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 216506 is about 465.3020524348. The cubic root of 216506 is about 60.0468153145.

The spelling of 216506 in words is "two hundred sixteen thousand, five hundred six".