221238528 has 108 divisors (see below), whose sum is σ = 685067040. Its totient is φ = 63200256.

The previous prime is 221238509. The next prime is 221238529. The reversal of 221238528 is 825832122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221238529) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 34693 + ... + 40571.

Almost surely, 2^221238528 is an apocalyptic number.

221238528 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 221238528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (342533520).

221238528 is an abundant number, since it is smaller than the sum of its proper divisors (463828512).

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

221238528 is an equidigital number, since it uses as much as digits as its factorization.

221238528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5912 (or 5891 counting only the distinct ones).

The product of its digits is 15360, while the sum is 33.

The square root of 221238528 is about 14874.0891485832. The cubic root of 221238528 is about 604.8117967521.

The spelling of 221238528 in words is "two hundred twenty-one million, two hundred thirty-eight thousand, five hundred twenty-eight".