218640240 has 480 divisors, whose sum is σ = 935940096. Its totient is φ = 44513280.

The previous prime is 218640223. The next prime is 218640283. The reversal of 218640240 is 42046812.

218640240 is a `hidden beast` number, since 2 + 18 + 640 + 2 + 4 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3079405 + ... + 3079475.

Almost surely, 2^218640240 is an apocalyptic number.

218640240 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 218640240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (467970048).

218640240 is an abundant number, since it is smaller than the sum of its proper divisors (717299856).

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

218640240 is a wasteful number, since it uses less digits than its factorization.

218640240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 218640240 is about 14786.4884269390. The cubic root of 218640240 is about 602.4347731021.

The spelling of 218640240 in words is "two hundred eighteen million, six hundred forty thousand, two hundred forty".