218556481 has 16 divisors (see below), whose sum is σ = 258128640. Its totient is φ = 182430720.

The previous prime is 218556433. The next prime is 218556491. The reversal of 218556481 is 184655812.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 218556481 - 2⁷ = 218556353 is a prime.

It is a super-2 number, since 2×218556481² = 95533870774206722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (218556491) 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 15 ways as a sum of consecutive naturals, for example, 23640 + ... + 31558.

It is an arithmetic number, because the mean of its divisors is an integer number (16133040).

Almost surely, 2^218556481 is an apocalyptic number.

It is an amenable number.

218556481 is a deficient number, since it is larger than the sum of its proper divisors (39572159).

218556481 is a wasteful number, since it uses less digits than its factorization.

218556481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8136.

The product of its digits is 76800, while the sum is 40.

The square root of 218556481 is about 14783.6558739711. The cubic root of 218556481 is about 602.3578342626.

The spelling of 218556481 in words is "two hundred eighteen million, five hundred fifty-six thousand, four hundred eighty-one".