218581804957656 has 256 divisors, whose sum is σ = 654992363520000. Its totient is φ = 59471141621760.

The previous prime is 218581804957631. The next prime is 218581804957717. The reversal of 218581804957656 is 656759408185812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 323824395 + ... + 324498693.

It is an arithmetic number, because the mean of its divisors is an integer number (2558563920000).

Almost surely, 2^{218581804957656} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218581804957656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (327496181760000).

218581804957656 is an abundant number, since it is smaller than the sum of its proper divisors (436410558562344).

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

218581804957656 is a wasteful number, since it uses less digits than its factorization.

218581804957656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 675342 (or 675338 counting only the distinct ones).

The product of its (nonzero) digits is 1161216000, while the sum is 75.

The spelling of 218581804957656 in words is "two hundred eighteen trillion, five hundred eighty-one billion, eight hundred four million, nine hundred fifty-seven thousand, six hundred fifty-six".