221116728 has 64 divisors (see below), whose sum is σ = 633749760. Its totient is φ = 62977536.

The previous prime is 221116723. The next prime is 221116741. The reversal of 221116728 is 827611122.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 221116695 and 221116704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221116723) 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, 56400 + ... + 60192.

It is an arithmetic number, because the mean of its divisors is an integer number (9902340).

Almost surely, 2^221116728 is an apocalyptic number.

221116728 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 221116728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316874880).

221116728 is an abundant number, since it is smaller than the sum of its proper divisors (412633032).

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

221116728 is a wasteful number, since it uses less digits than its factorization.

221116728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4156 (or 4152 counting only the distinct ones).

The product of its digits is 2688, while the sum is 30.

The square root of 221116728 is about 14869.9942165423. The cubic root of 221116728 is about 604.7007859496.

The spelling of 221116728 in words is "two hundred twenty-one million, one hundred sixteen thousand, seven hundred twenty-eight".