218399 has 8 divisors (see below), whose sum is σ = 239760. Its totient is φ = 198016.

The previous prime is 218389. The next prime is 218401. The reversal of 218399 is 993812.

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

It is not a de Polignac number, because 218399 - 2⁸ = 218143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218389) 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 7 ways as a sum of consecutive naturals, for example, 272 + ... + 714.

It is an arithmetic number, because the mean of its divisors is an integer number (29970).

2²¹⁸³⁹⁹ is an apocalyptic number.

218399 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

218399 is a deficient number, since it is larger than the sum of its proper divisors (21361).

218399 is a wasteful number, since it uses less digits than its factorization.

218399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489.

The product of its digits is 3888, while the sum is 32.

The square root of 218399 is about 467.3317879195. The cubic root of 218399 is about 60.2213123070.

The spelling of 218399 in words is "two hundred eighteen thousand, three hundred ninety-nine".