218564 has 12 divisors (see below), whose sum is σ = 386988. Its totient is φ = 108000.

The previous prime is 218551. The next prime is 218579. The reversal of 218564 is 465812.

218564 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 160000 + 58564 = 400^2 + 242^2 .

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, 134 + ... + 674.

It is an arithmetic number, because the mean of its divisors is an integer number (32249).

2²¹⁸⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

218564 is a deficient number, since it is larger than the sum of its proper divisors (168424).

218564 is a wasteful number, since it uses less digits than its factorization.

218564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646 (or 644 counting only the distinct ones).

The product of its digits is 1920, while the sum is 26.

The square root of 218564 is about 467.5082886966. The cubic root of 218564 is about 60.2364741823.

It can be divided in two parts, 2 and 18564, that multiplied together give a triangular number (37128 = T₂₇₂).

The spelling of 218564 in words is "two hundred eighteen thousand, five hundred sixty-four".