28280628 has 18 divisors (see below), whose sum is σ = 71487234. Its totient is φ = 9426864.

The previous prime is 28280621. The next prime is 28280669. The reversal of 28280628 is 82608282.

28280628 is a `hidden beast` number, since 2 + 8 + 28 + 0 + 628 = 666.

It can be written as a sum of positive squares in only one way, i.e., 26811684 + 1468944 = 5178^2 + 1212^2 .

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: 785573 = 28280628 / (2 + 8 + 2 + 8 + 0 + 6 + 2 + 8).

It is a junction number, because it is equal to n+sod(n) for n = 28280592 and 28280601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28280621) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 392751 + ... + 392822.

It is an arithmetic number, because the mean of its divisors is an integer number (3971513).

Almost surely, 2^28280628 is an apocalyptic number.

It is an amenable number.

28280628 is an abundant number, since it is smaller than the sum of its proper divisors (43206606).

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

28280628 is a wasteful number, since it uses less digits than its factorization.

28280628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785583 (or 785578 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 36.

The square root of 28280628 is about 5317.9533657226. The cubic root of 28280628 is about 304.6699933294.

The spelling of 28280628 in words is "twenty-eight million, two hundred eighty thousand, six hundred twenty-eight".