218308 has 6 divisors (see below), whose sum is σ = 382046. Its totient is φ = 109152.

The previous prime is 218287. The next prime is 218357. The reversal of 218308 is 803812.

It can be written as a sum of positive squares in only one way, i.e., 186624 + 31684 = 432^2 + 178^2 .

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27285 + ... + 27292.

2²¹⁸³⁰⁸ is an apocalyptic number.

It is an amenable number.

218308 is a deficient number, since it is larger than the sum of its proper divisors (163738).

218308 is a wasteful number, since it uses less digits than its factorization.

218308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54581 (or 54579 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 218308 is about 467.2344165406. The cubic root of 218308 is about 60.2129470356.

The spelling of 218308 in words is "two hundred eighteen thousand, three hundred eight".