221188128 has 96 divisors (see below), whose sum is σ = 665957376. Its totient is φ = 62969088.

The previous prime is 221188103. The next prime is 221188147. The reversal of 221188128 is 821881122.

221188128 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 297325 + ... + 298067.

It is an arithmetic number, because the mean of its divisors is an integer number (6937056).

Almost surely, 2^221188128 is an apocalyptic number.

221188128 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 221188128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332978688).

221188128 is an abundant number, since it is smaller than the sum of its proper divisors (444769248).

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

221188128 is a wasteful number, since it uses less digits than its factorization.

221188128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1206 (or 1198 counting only the distinct ones).

The product of its digits is 4096, while the sum is 33.

The square root of 221188128 is about 14872.3948306922. The cubic root of 221188128 is about 604.7658661904.

The spelling of 221188128 in words is "two hundred twenty-one million, one hundred eighty-eight thousand, one hundred twenty-eight".