218390 has 8 divisors (see below), whose sum is σ = 393120. Its totient is φ = 87352.

The previous prime is 218389. The next prime is 218401. The reversal of 218390 is 93812.

218390 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10910 + ... + 10929.

It is an arithmetic number, because the mean of its divisors is an integer number (49140).

2²¹⁸³⁹⁰ is an apocalyptic number.

218390 is a deficient number, since it is larger than the sum of its proper divisors (174730).

218390 is a wasteful number, since it uses less digits than its factorization.

218390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21846.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 218390 is about 467.3221586871. The cubic root of 218390 is about 60.2204850760.

The spelling of 218390 in words is "two hundred eighteen thousand, three hundred ninety".