28878065 has 4 divisors (see below), whose sum is σ = 34653684. Its totient is φ = 23102448.

The previous prime is 28878049. The next prime is 28878067. The reversal of 28878065 is 56087882.

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 18386944 + 10491121 = 4288^2 + 3239^2 .

It is a cyclic number.

It is not a de Polignac number, because 28878065 - 2⁴ = 28878049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28878067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2887802 + ... + 2887811.

It is an arithmetic number, because the mean of its divisors is an integer number (8663421).

Almost surely, 2^28878065 is an apocalyptic number.

It is an amenable number.

28878065 is a deficient number, since it is larger than the sum of its proper divisors (5775619).

28878065 is an equidigital number, since it uses as much as digits as its factorization.

28878065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5775618.

The product of its (nonzero) digits is 215040, while the sum is 44.

The square root of 28878065 is about 5373.8315008939. The cubic root of 28878065 is about 306.8004765508.

The spelling of 28878065 in words is "twenty-eight million, eight hundred seventy-eight thousand, sixty-five".