218138928 has 160 divisors (see below), whose sum is σ = 679004160. Its totient is φ = 59028480.

The previous prime is 218138861. The next prime is 218138933. The reversal of 218138928 is 829831812.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 218138928.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 594201 + ... + 594567.

It is an arithmetic number, because the mean of its divisors is an integer number (4243776).

Almost surely, 2^218138928 is an apocalyptic number.

218138928 is a gapful number since it is divisible by the number (28) 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 218138928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (339502080).

218138928 is an abundant number, since it is smaller than the sum of its proper divisors (460865232).

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

218138928 is a wasteful number, since it uses less digits than its factorization.

218138928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475 (or 469 counting only the distinct ones).

The product of its digits is 55296, while the sum is 42.

The square root of 218138928 is about 14769.5270066445. The cubic root of 218138928 is about 601.9739873897.

The spelling of 218138928 in words is "two hundred eighteen million, one hundred thirty-eight thousand, nine hundred twenty-eight".