218385561 has 8 divisors (see below), whose sum is σ = 291274720. Its totient is φ = 145543392.

The previous prime is 218385539. The next prime is 218385569. The reversal of 218385561 is 165583812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 218385561 - 2¹⁵ = 218352793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218385569) 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 7 ways as a sum of consecutive naturals, for example, 1110 + ... + 20928.

It is an arithmetic number, because the mean of its divisors is an integer number (36409340).

Almost surely, 2^218385561 is an apocalyptic number.

It is an amenable number.

218385561 is a deficient number, since it is larger than the sum of its proper divisors (72889159).

218385561 is a wasteful number, since it uses less digits than its factorization.

218385561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23495.

The product of its digits is 57600, while the sum is 39.

The square root of 218385561 is about 14777.8740351919. The cubic root of 218385561 is about 602.2007705895.

The spelling of 218385561 in words is "two hundred eighteen million, three hundred eighty-five thousand, five hundred sixty-one".