218642 has 4 divisors (see below), whose sum is σ = 327966. Its totient is φ = 109320.

The previous prime is 218641. The next prime is 218651. The reversal of 218642 is 246812.

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., 192721 + 25921 = 439^2 + 161^2 .

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (218641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54659 + ... + 54662.

2²¹⁸⁶⁴² is an apocalyptic number.

218642 is a deficient number, since it is larger than the sum of its proper divisors (109324).

218642 is a wasteful number, since it uses less digits than its factorization.

218642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109323.

The product of its digits is 768, while the sum is 23.

The square root of 218642 is about 467.5917022360. The cubic root of 218642 is about 60.2436389582.

The spelling of 218642 in words is "two hundred eighteen thousand, six hundred forty-two".