218242 has 4 divisors (see below), whose sum is σ = 327366. Its totient is φ = 109120.

The previous prime is 218233. The next prime is 218249. The reversal of 218242 is 242812.

218242 is nontrivially palindromic in base 12.

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., 201601 + 16641 = 449^2 + 129^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (218249) by changing a digit.

218242 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54559 + ... + 54562.

2²¹⁸²⁴² is an apocalyptic number.

218242 is a deficient number, since it is larger than the sum of its proper divisors (109124).

218242 is a wasteful number, since it uses less digits than its factorization.

218242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109123.

The product of its digits is 256, while the sum is 19.

The square root of 218242 is about 467.1637828428. The cubic root of 218242 is about 60.2068784611.

The spelling of 218242 in words is "two hundred eighteen thousand, two hundred forty-two".