218491164 has 18 divisors (see below), whose sum is σ = 552297200. Its totient is φ = 72830376.

The previous prime is 218491153. The next prime is 218491177. The reversal of 218491164 is 461194812.

218491164 is a `hidden beast` number, since 2 + 1 + 8 + 491 + 164 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 6069199 = 218491164 / (2 + 1 + 8 + 4 + 9 + 1 + 1 + 6 + 4).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3034564 + ... + 3034635.

Almost surely, 2^218491164 is an apocalyptic number.

It is an amenable number.

218491164 is an abundant number, since it is smaller than the sum of its proper divisors (333806036).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218491164 is a wasteful number, since it uses less digits than its factorization.

218491164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6069209 (or 6069204 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 218491164 is about 14781.4466139143. The cubic root of 218491164 is about 602.2978221221.

The spelling of 218491164 in words is "two hundred eighteen million, four hundred ninety-one thousand, one hundred sixty-four".