216538 has 8 divisors (see below), whose sum is σ = 371232. Its totient is φ = 92796.

The previous prime is 216523. The next prime is 216551. The reversal of 216538 is 835612.

It is a happy number.

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

It is a congruent number.

It is an unprimeable 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 3 ways as a sum of consecutive naturals, for example, 7720 + ... + 7747.

It is an arithmetic number, because the mean of its divisors is an integer number (46404).

2²¹⁶⁵³⁸ is an apocalyptic number.

216538 is a deficient number, since it is larger than the sum of its proper divisors (154694).

216538 is a wasteful number, since it uses less digits than its factorization.

216538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15476.

The product of its digits is 1440, while the sum is 25.

The square root of 216538 is about 465.3364374300. The cubic root of 216538 is about 60.0497735134.

The spelling of 216538 in words is "two hundred sixteen thousand, five hundred thirty-eight".