28778609 has 8 divisors (see below), whose sum is σ = 29090880. Its totient is φ = 28468336.

The previous prime is 28778587. The next prime is 28778611. The reversal of 28778609 is 90687782.

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 28778609 - 2¹² = 28774513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28778669) 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, 64742 + ... + 65184.

It is an arithmetic number, because the mean of its divisors is an integer number (3636360).

Almost surely, 2^28778609 is an apocalyptic number.

It is an amenable number.

28778609 is a deficient number, since it is larger than the sum of its proper divisors (312271).

28778609 is a wasteful number, since it uses less digits than its factorization.

28778609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999.

The product of its (nonzero) digits is 338688, while the sum is 47.

The square root of 28778609 is about 5364.5697870379. The cubic root of 28778609 is about 306.4478646930.

The spelling of 28778609 in words is "twenty-eight million, seven hundred seventy-eight thousand, six hundred nine".