218907081640 has 64 divisors (see below), whose sum is σ = 531654253200. Its totient is φ = 80640479232.

The previous prime is 218907081637. The next prime is 218907081667. The reversal of 218907081640 is 46180709812.

218907081640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 52056072964 + 166851008676 = 228158^2 + 408474^2 .

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 260955 + ... + 711274.

Almost surely, 2^218907081640 is an apocalyptic number.

218907081640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218907081640 is an abundant number, since it is smaller than the sum of its proper divisors (312747171560).

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

218907081640 is a wasteful number, since it uses less digits than its factorization.

218907081640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972686 (or 972682 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 46.

The spelling of 218907081640 in words is "two hundred eighteen billion, nine hundred seven million, eighty-one thousand, six hundred forty".