218965 has 4 divisors (see below), whose sum is σ = 262764. Its totient is φ = 175168.

The previous prime is 218963. The next prime is 218969. The reversal of 218965 is 569812.

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 154449 + 64516 = 393^2 + 254^2 .

It is a cyclic number.

It is not a de Polignac number, because 218965 - 2¹ = 218963 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21892 + ... + 21901.

It is an arithmetic number, because the mean of its divisors is an integer number (65691).

2²¹⁸⁹⁶⁵ is an apocalyptic number.

It is an amenable number.

218965 is a deficient number, since it is larger than the sum of its proper divisors (43799).

218965 is an equidigital number, since it uses as much as digits as its factorization.

218965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43798.

The product of its digits is 4320, while the sum is 31.

The square root of 218965 is about 467.9369615664. The cubic root of 218965 is about 60.2732903535.

The spelling of 218965 in words is "two hundred eighteen thousand, nine hundred sixty-five".