218681856 has 100 divisors (see below), whose sum is σ = 652831542. Its totient is φ = 72880128.

The previous prime is 218681851. The next prime is 218681873. The reversal of 218681856 is 658186812.

It can be written as a sum of positive squares in only one way, i.e., 187142400 + 31539456 = 13680^2 + 5616^2 .

It is not an unprimeable number, because it can be changed into a prime (218681851) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 38836 + ... + 44108.

Almost surely, 2^218681856 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 218681856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (326415771).

218681856 is an abundant number, since it is smaller than the sum of its proper divisors (434149686).

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

218681856 is an frugal number, since it uses more digits than its factorization.

218681856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5303 (or 5278 counting only the distinct ones).

The product of its digits is 184320, while the sum is 45.

The square root of 218681856 is about 14787.8955906512. The cubic root of 218681856 is about 602.4729931709.

The spelling of 218681856 in words is "two hundred eighteen million, six hundred eighty-one thousand, eight hundred fifty-six".