28306987 has 4 divisors (see below), whose sum is σ = 29283120. Its totient is φ = 27330856.

The previous prime is 28306981. The next prime is 28307003. The reversal of 28306987 is 78960382.

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 28306987 - 2¹⁵ = 28274219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28306981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 488023 + ... + 488080.

It is an arithmetic number, because the mean of its divisors is an integer number (7320780).

Almost surely, 2^28306987 is an apocalyptic number.

28306987 is a deficient number, since it is larger than the sum of its proper divisors (976133).

28306987 is an equidigital number, since it uses as much as digits as its factorization.

28306987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 976132.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 28306987 is about 5320.4310915564. The cubic root of 28306987 is about 304.7646199717.

The spelling of 28306987 in words is "twenty-eight million, three hundred six thousand, nine hundred eighty-seven".