218906 has 4 divisors (see below), whose sum is σ = 328362. Its totient is φ = 109452.

The previous prime is 218887. The next prime is 218923. The reversal of 218906 is 609812.

218906 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 207025 + 11881 = 455^2 + 109^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54725 + ... + 54728.

2²¹⁸⁹⁰⁶ is an apocalyptic number.

218906 is a deficient number, since it is larger than the sum of its proper divisors (109456).

218906 is a wasteful number, since it uses less digits than its factorization.

218906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109455.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 218906 is about 467.8739146394. The cubic root of 218906 is about 60.2678763321.

The spelling of 218906 in words is "two hundred eighteen thousand, nine hundred six".