216541 has 4 divisors (see below), whose sum is σ = 233212. Its totient is φ = 199872.

The previous prime is 216523. The next prime is 216551. The reversal of 216541 is 145612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 143641 + 72900 = 379^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 216541 - 2⁵ = 216509 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a nialpdrome in base 13.

It is a congruent number.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8316 + ... + 8341.

It is an arithmetic number, because the mean of its divisors is an integer number (58303).

2²¹⁶⁵⁴¹ is an apocalyptic number.

It is an amenable number.

216541 is a deficient number, since it is larger than the sum of its proper divisors (16671).

216541 is a wasteful number, since it uses less digits than its factorization.

216541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16670.

The product of its digits is 240, while the sum is 19.

The square root of 216541 is about 465.3396608930. The cubic root of 216541 is about 60.0500508296.

It can be divided in two parts, 216 and 541, that added together give a palindrome (757).

The spelling of 216541 in words is "two hundred sixteen thousand, five hundred forty-one".