218428 has 24 divisors (see below), whose sum is σ = 453600. Its totient is φ = 90048.

The previous prime is 218423. The next prime is 218437. The reversal of 218428 is 824812.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 678 + ... + 946.

It is an arithmetic number, because the mean of its divisors is an integer number (18900).

2²¹⁸⁴²⁸ is an apocalyptic number.

218428 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 218428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226800).

218428 is an abundant number, since it is smaller than the sum of its proper divisors (235172).

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

218428 is a wasteful number, since it uses less digits than its factorization.

218428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309 (or 307 counting only the distinct ones).

The product of its digits is 1024, while the sum is 25.

The square root of 218428 is about 467.3628140963. The cubic root of 218428 is about 60.2239776745.

It can be divided in two parts, 218 and 428, that added together give a palindrome (646).

The spelling of 218428 in words is "two hundred eighteen thousand, four hundred twenty-eight".