218398720 has 128 divisors (see below), whose sum is σ = 553639680. Its totient is φ = 82575360.

The previous prime is 218398703. The next prime is 218398721. The reversal of 218398720 is 27893812.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (218398721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5079019 + ... + 5079061.

It is an arithmetic number, because the mean of its divisors is an integer number (4325310).

Almost surely, 2^218398720 is an apocalyptic number.

218398720 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 218398720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276819840).

218398720 is an abundant number, since it is smaller than the sum of its proper divisors (335240960).

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

218398720 is an frugal number, since it uses more digits than its factorization.

218398720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 218398720 is about 14778.3192549085. The cubic root of 218398720 is about 602.2128657127.

The spelling of 218398720 in words is "two hundred eighteen million, three hundred ninety-eight thousand, seven hundred twenty".