221304144 has 80 divisors (see below), whose sum is σ = 589248000. Its totient is φ = 71530368.

The previous prime is 221304131. The next prime is 221304151. The reversal of 221304144 is 441403122.

221304144 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 221304144.

It is a congruent number.

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, 369157 + ... + 369755.

It is an arithmetic number, because the mean of its divisors is an integer number (7365600).

Almost surely, 2^221304144 is an apocalyptic number.

221304144 is a gapful number since it is divisible by the number (24) 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 221304144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294624000).

221304144 is an abundant number, since it is smaller than the sum of its proper divisors (367943856).

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

221304144 is a wasteful number, since it uses less digits than its factorization.

221304144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 832 (or 826 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 221304144 is about 14876.2946999581. The cubic root of 221304144 is about 604.8715835178.

Adding to 221304144 its reverse (441403122), we get a palindrome (662707266).

The spelling of 221304144 in words is "two hundred twenty-one million, three hundred four thousand, one hundred forty-four".