218165 has 4 divisors (see below), whose sum is σ = 261804. Its totient is φ = 174528.

The previous prime is 218149. The next prime is 218171. The reversal of 218165 is 561812.

218165 = T₁₆₃ + T₁₆₄ + ... + T₁₇₇.

218165 is digitally balanced in base 2, 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 2 ways, for example, as 148996 + 69169 = 386^2 + 263^2 .

It is a cyclic number.

It is not a de Polignac number, because 218165 - 2⁴ = 218149 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 218165.

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, 21812 + ... + 21821.

It is an arithmetic number, because the mean of its divisors is an integer number (65451).

2²¹⁸¹⁶⁵ is an apocalyptic number.

It is an amenable number.

218165 is a deficient number, since it is larger than the sum of its proper divisors (43639).

218165 is an equidigital number, since it uses as much as digits as its factorization.

218165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43638.

The product of its digits is 480, while the sum is 23.

The square root of 218165 is about 467.0813633619. The cubic root of 218165 is about 60.1997969110.

Adding to 218165 its reverse (561812), we get a palindrome (779977).

It can be divided in two parts, 218 and 165, that added together give a palindrome (383).

The spelling of 218165 in words is "two hundred eighteen thousand, one hundred sixty-five".