28280287 has 4 divisors (see below), whose sum is σ = 32320336. Its totient is φ = 24240240.

The previous prime is 28280269. The next prime is 28280297. The reversal of 28280287 is 78208282.

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 28280287 - 2¹⁹ = 27755999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28280237) 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, 2020014 + ... + 2020027.

It is an arithmetic number, because the mean of its divisors is an integer number (8080084).

Almost surely, 2^28280287 is an apocalyptic number.

28280287 is a deficient number, since it is larger than the sum of its proper divisors (4040049).

28280287 is an equidigital number, since it uses as much as digits as its factorization.

28280287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4040048.

The product of its (nonzero) digits is 28672, while the sum is 37.

The square root of 28280287 is about 5317.9213044196. The cubic root of 28280287 is about 304.6687687823.

The spelling of 28280287 in words is "twenty-eight million, two hundred eighty thousand, two hundred eighty-seven".