7728228 has 18 divisors (see below), whose sum is σ = 19535334. Its totient is φ = 2576064.

The previous prime is 7728221. The next prime is 7728271. The reversal of 7728228 is 8228277.

It can be written as a sum of positive squares in only one way, i.e., 5531904 + 2196324 = 2352^2 + 1482^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 214673 = 7728228 / (7 + 7 + 2 + 8 + 2 + 2 + 8).

It is a junction number, because it is equal to n+sod(n) for n = 7728192 and 7728201.

It is not an unprimeable number, because it can be changed into a prime (7728221) 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 5 ways as a sum of consecutive naturals, for example, 107301 + ... + 107372.

Almost surely, 2^7728228 is an apocalyptic number.

It is an amenable number.

7728228 is an abundant number, since it is smaller than the sum of its proper divisors (11807106).

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

7728228 is a wasteful number, since it uses less digits than its factorization.

7728228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214683 (or 214678 counting only the distinct ones).

The product of its digits is 25088, while the sum is 36.

The square root of 7728228 is about 2779.9690645761. The cubic root of 7728228 is about 197.7090922354.

The spelling of 7728228 in words is "seven million, seven hundred twenty-eight thousand, two hundred twenty-eight".