28778565 has 8 divisors (see below), whose sum is σ = 46045728. Its totient is φ = 15348560.

The previous prime is 28778551. The next prime is 28778573. The reversal of 28778565 is 56587782.

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

It is not a de Polignac number, because 28778565 - 2⁷ = 28778437 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 959271 + ... + 959300.

It is an arithmetic number, because the mean of its divisors is an integer number (5755716).

Almost surely, 2^28778565 is an apocalyptic number.

It is an amenable number.

28778565 is a deficient number, since it is larger than the sum of its proper divisors (17267163).

28778565 is a wasteful number, since it uses less digits than its factorization.

28778565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1918579.

The product of its digits is 940800, while the sum is 48.

The square root of 28778565 is about 5364.5656860551. The cubic root of 28778565 is about 306.4477085155.

The spelling of 28778565 in words is "twenty-eight million, seven hundred seventy-eight thousand, five hundred sixty-five".