216559728 has 120 divisors (see below), whose sum is σ = 755654016. Its totient is φ = 56246400.

The previous prime is 216559687. The next prime is 216559747. The reversal of 216559728 is 827955612.

216559728 is a `hidden beast` number, since 21 + 6 + 559 + 72 + 8 = 666.

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, 1323 + ... + 20853.

Almost surely, 2^216559728 is an apocalyptic number.

216559728 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 216559728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (377827008).

216559728 is an abundant number, since it is smaller than the sum of its proper divisors (539094288).

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

216559728 is a wasteful number, since it uses less digits than its factorization.

216559728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19563 (or 19554 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The square root of 216559728 is about 14715.9684696591. The cubic root of 216559728 is about 600.5178196428.

The spelling of 216559728 in words is "two hundred sixteen million, five hundred fifty-nine thousand, seven hundred twenty-eight".