218481 has 8 divisors (see below), whose sum is σ = 306720. Its totient is φ = 137952.

The previous prime is 218479. The next prime is 218509. The reversal of 218481 is 184812.

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

It is not a de Polignac number, because 218481 - 2¹ = 218479 is a prime.

It is a super-2 number, since 2×218481² = 95467894722, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (218401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1860 + ... + 1973.

It is an arithmetic number, because the mean of its divisors is an integer number (38340).

2²¹⁸⁴⁸¹ is an apocalyptic number.

It is an amenable number.

218481 is a deficient number, since it is larger than the sum of its proper divisors (88239).

218481 is a wasteful number, since it uses less digits than its factorization.

218481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3855.

The product of its digits is 512, while the sum is 24.

The square root of 218481 is about 467.4195117879. The cubic root of 218481 is about 60.2288482538.

The spelling of 218481 in words is "two hundred eighteen thousand, four hundred eighty-one".