28728005 has 8 divisors (see below), whose sum is σ = 34829592. Its totient is φ = 22745088.

The previous prime is 28728001. The next prime is 28728013. The reversal of 28728005 is 50082782.

It can be written as a sum of positive squares in 4 ways, for example, as 521284 + 28206721 = 722^2 + 5311^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28728005 - 2² = 28728001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29132 + ... + 30101.

It is an arithmetic number, because the mean of its divisors is an integer number (4353699).

Almost surely, 2^28728005 is an apocalyptic number.

It is an amenable number.

28728005 is a deficient number, since it is larger than the sum of its proper divisors (6101587).

28728005 is an equidigital number, since it uses as much as digits as its factorization.

28728005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59335.

The product of its (nonzero) digits is 8960, while the sum is 32.

The square root of 28728005 is about 5359.8512106214. The cubic root of 28728005 is about 306.2681410884.

The spelling of 28728005 in words is "twenty-eight million, seven hundred twenty-eight thousand, five".