218988640 has 96 divisors (see below), whose sum is σ = 562222080. Its totient is φ = 80123904.

The previous prime is 218988631. The next prime is 218988641. The reversal of 218988640 is 46889812.

218988640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218988641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 263746 + ... + 264574.

It is an arithmetic number, because the mean of its divisors is an integer number (5856480).

Almost surely, 2^218988640 is an apocalyptic number.

218988640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218988640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (281111040).

218988640 is an abundant number, since it is smaller than the sum of its proper divisors (343233440).

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

218988640 is a wasteful number, since it uses less digits than its factorization.

218988640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 984 (or 976 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 46.

The square root of 218988640 is about 14798.2647631403. The cubic root of 218988640 is about 602.7545935964.

The spelling of 218988640 in words is "two hundred eighteen million, nine hundred eighty-eight thousand, six hundred forty".