216240 has 80 divisors (see below), whose sum is σ = 723168. Its totient is φ = 53248.

The previous prime is 216233. The next prime is 216259. The reversal of 216240 is 42612.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-3 number, since 3×216240³ = 30333976975872000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4054 + ... + 4106.

2²¹⁶²⁴⁰ is an apocalyptic number.

216240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 216240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (361584).

216240 is an abundant number, since it is smaller than the sum of its proper divisors (506928).

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

216240 is a wasteful number, since it uses less digits than its factorization.

216240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 216240 is about 465.0161287525. The cubic root of 216240 is about 60.0222139968.

Subtracting from 216240 its sum of digits (15), we obtain a square (216225 = 465²).

Adding to 216240 its reverse (42612), we get a palindrome (258852).

The spelling of 216240 in words is "two hundred sixteen thousand, two hundred forty".