28551665 has 4 divisors (see below), whose sum is σ = 34262004. Its totient is φ = 22841328.

The previous prime is 28551647. The next prime is 28551667. The reversal of 28551665 is 56615582.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3139984 + 25411681 = 1772^2 + 5041^2 .

It is a cyclic number.

It is not a de Polignac number, because 28551665 - 2⁸ = 28551409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28551667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2855162 + ... + 2855171.

It is an arithmetic number, because the mean of its divisors is an integer number (8565501).

Almost surely, 2^28551665 is an apocalyptic number.

It is an amenable number.

28551665 is a deficient number, since it is larger than the sum of its proper divisors (5710339).

28551665 is an equidigital number, since it uses as much as digits as its factorization.

28551665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5710338.

The product of its digits is 72000, while the sum is 38.

The square root of 28551665 is about 5343.3758056120. The cubic root of 28551665 is about 305.6402032269.

The spelling of 28551665 in words is "twenty-eight million, five hundred fifty-one thousand, six hundred sixty-five".