225728128 has 32 divisors (see below), whose sum is σ = 455132160. Its totient is φ = 111499008.

The previous prime is 225728101. The next prime is 225728147. The reversal of 225728128 is 821827522.

It is a happy number.

225728128 is a nontrivial binomial coefficient, being equal to C(21248, 2).

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1 + ... + 21247.

It is an arithmetic number, because the mean of its divisors is an integer number (14222880).

Almost surely, 2^225728128 is an apocalyptic number.

225728128 is the 21247-th triangular number and also the 10624-th hexagonal number.

225728128 is the 7083-rd centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 225728128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (227566080).

225728128 is an abundant number, since it is smaller than the sum of its proper divisors (229404032).

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

225728128 is an equidigital number, since it uses as much as digits as its factorization.

225728128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21344 (or 21332 counting only the distinct ones).

The product of its digits is 35840, while the sum is 37.

The square root of 225728128 is about 15024.2513291012. The cubic root of 225728128 is about 608.8755851802.

The spelling of 225728128 in words is "two hundred twenty-five million, seven hundred twenty-eight thousand, one hundred twenty-eight".