28728945 has 96 divisors (see below), whose sum is σ = 61395840. Its totient is φ = 12700800.

The previous prime is 28728941. The next prime is 28728949. The reversal of 28728945 is 54982782.

It is an interprime number because it is at equal distance from previous prime (28728941) and next prime (28728949).

It is not a de Polignac number, because 28728945 - 2² = 28728941 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28728945.

It is not an unprimeable number, because it can be changed into a prime (28728941) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 284395 + ... + 284495.

It is an arithmetic number, because the mean of its divisors is an integer number (639540).

Almost surely, 2^28728945 is an apocalyptic number.

It is an amenable number.

28728945 is an abundant number, since it is smaller than the sum of its proper divisors (32666895).

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

28728945 is a wasteful number, since it uses less digits than its factorization.

28728945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 159 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 28728945 is about 5359.9388989055. The cubic root of 28728945 is about 306.2714814864.

The spelling of 28728945 in words is "twenty-eight million, seven hundred twenty-eight thousand, nine hundred forty-five".