218660220 has 72 divisors (see below), whose sum is σ = 668186064. Its totient is φ = 57877248.

The previous prime is 218660219. The next prime is 218660249. The reversal of 218660220 is 22066812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20227 + ... + 29093.

It is an arithmetic number, because the mean of its divisors is an integer number (9280362).

Almost surely, 2^218660220 is an apocalyptic number.

218660220 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 218660220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (334093032).

218660220 is an abundant number, since it is smaller than the sum of its proper divisors (449525844).

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

218660220 is a wasteful number, since it uses less digits than its factorization.

218660220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9019 (or 9014 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 218660220 is about 14787.1640283051. The cubic root of 218660220 is about 602.4531233078.

The spelling of 218660220 in words is "two hundred eighteen million, six hundred sixty thousand, two hundred twenty".