221548728 has 64 divisors (see below), whose sum is σ = 571253760. Its totient is φ = 71559936.

The previous prime is 221548681. The next prime is 221548729. The reversal of 221548728 is 827845122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221548729) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140601 + ... + 142167.

It is an arithmetic number, because the mean of its divisors is an integer number (8925840).

Almost surely, 2^221548728 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 221548728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (285626880).

221548728 is an abundant number, since it is smaller than the sum of its proper divisors (349705032).

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

221548728 is a wasteful number, since it uses less digits than its factorization.

221548728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1756 (or 1752 counting only the distinct ones).

The product of its digits is 71680, while the sum is 39.

The square root of 221548728 is about 14884.5130252891. The cubic root of 221548728 is about 605.0943349474.

The spelling of 221548728 in words is "two hundred twenty-one million, five hundred forty-eight thousand, seven hundred twenty-eight".