28708387 has 4 divisors (see below), whose sum is σ = 29634496. Its totient is φ = 27782280.

The previous prime is 28708357. The next prime is 28708403. The reversal of 28708387 is 78380782.

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

It is a cyclic number.

It is not a de Polignac number, because 28708387 - 2¹⁹ = 28184099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28708327) 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, 463008 + ... + 463069.

It is an arithmetic number, because the mean of its divisors is an integer number (7408624).

Almost surely, 2^28708387 is an apocalyptic number.

28708387 is a deficient number, since it is larger than the sum of its proper divisors (926109).

28708387 is an equidigital number, since it uses as much as digits as its factorization.

28708387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 926108.

The product of its (nonzero) digits is 150528, while the sum is 43.

The square root of 28708387 is about 5358.0208099633. The cubic root of 28708387 is about 306.1984096354.

The spelling of 28708387 in words is "twenty-eight million, seven hundred eight thousand, three hundred eighty-seven".