221306528 has 48 divisors (see below), whose sum is σ = 461391840. Its totient is φ = 104198400.

The previous prime is 221306473. The next prime is 221306531. The reversal of 221306528 is 825603122.

It is a self number, because there is not a number n which added to its sum of digits gives 221306528.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109043 + ... + 111053.

It is an arithmetic number, because the mean of its divisors is an integer number (9612330).

Almost surely, 2^221306528 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221306528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (230695920).

221306528 is an abundant number, since it is smaller than the sum of its proper divisors (240085312).

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

221306528 is a wasteful number, since it uses less digits than its factorization.

221306528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2221 (or 2213 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 221306528 is about 14876.3748272219. The cubic root of 221306528 is about 604.8737555041.

The spelling of 221306528 in words is "two hundred twenty-one million, three hundred six thousand, five hundred twenty-eight".