28728540 has 48 divisors (see below), whose sum is σ = 89379360. Its totient is φ = 7660800.

The previous prime is 28728533. The next prime is 28728547. The reversal of 28728540 is 4582782.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28728533) and next prime (28728547).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28728495 and 28728504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26061 + ... + 27140.

It is an arithmetic number, because the mean of its divisors is an integer number (1862070).

Almost surely, 2^28728540 is an apocalyptic number.

28728540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28728540 is an abundant number, since it is smaller than the sum of its proper divisors (60650820).

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

28728540 is a wasteful number, since it uses less digits than its factorization.

28728540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53219 (or 53211 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 36.

The square root of 28728540 is about 5359.9011184909. The cubic root of 28728540 is about 306.2700422813.

The spelling of 28728540 in words is "twenty-eight million, seven hundred twenty-eight thousand, five hundred forty".