218589359981 has 2 divisors, whose sum is σ = 218589359982. Its totient is φ = 218589359980.

The previous prime is 218589359977. The next prime is 218589360019. The reversal of 218589359981 is 189953985812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 169245846025 + 49343513956 = 411395^2 + 222134^2 .

It is a cyclic number.

It is not a de Polignac number, because 218589359981 - 2² = 218589359977 is a prime.

It is a super-3 number, since 3×218589359981³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218589355981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109294679990 + 109294679991.

It is an arithmetic number, because the mean of its divisors is an integer number (109294679991).

Almost surely, 2^218589359981 is an apocalyptic number.

It is an amenable number.

218589359981 is a deficient number, since it is larger than the sum of its proper divisors (1).

218589359981 is an equidigital number, since it uses as much as digits as its factorization.

218589359981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55987200, while the sum is 68.

It can be divided in two parts, 21858 and 9359981, that added together give a palindrome (9381839).

The spelling of 218589359981 in words is "two hundred eighteen billion, five hundred eighty-nine million, three hundred fifty-nine thousand, nine hundred eighty-one".