218531864 has 16 divisors (see below), whose sum is σ = 409978800. Its totient is φ = 109204192.

The previous prime is 218531839. The next prime is 218531867. The reversal of 218531864 is 468135812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218531867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9614 + ... + 23010.

It is an arithmetic number, because the mean of its divisors is an integer number (25623675).

Almost surely, 2^218531864 is an apocalyptic number.

It is an amenable number.

218531864 is a deficient number, since it is larger than the sum of its proper divisors (191446936).

218531864 is a wasteful number, since it uses less digits than its factorization.

218531864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15442 (or 15438 counting only the distinct ones).

The product of its digits is 46080, while the sum is 38.

The square root of 218531864 is about 14782.8232756805. The cubic root of 218531864 is about 602.3352179889.

The spelling of 218531864 in words is "two hundred eighteen million, five hundred thirty-one thousand, eight hundred sixty-four".