28287989 has 4 divisors (see below), whose sum is σ = 28388940. Its totient is φ = 28187040.

The previous prime is 28287929. The next prime is 28288019. The reversal of 28287989 is 98978282.

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

It can be written as a sum of positive squares in 2 ways, for example, as 23522500 + 4765489 = 4850^2 + 2183^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28287989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28287989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28287929) 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, 50054 + ... + 50615.

It is an arithmetic number, because the mean of its divisors is an integer number (7097235).

Almost surely, 2^28287989 is an apocalyptic number.

It is an amenable number.

28287989 is a deficient number, since it is larger than the sum of its proper divisors (100951).

28287989 is a wasteful number, since it uses less digits than its factorization.

28287989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100950.

The product of its digits is 1161216, while the sum is 53.

The square root of 28287989 is about 5318.6454102525. The cubic root of 28287989 is about 304.6964246292.

The spelling of 28287989 in words is "twenty-eight million, two hundred eighty-seven thousand, nine hundred eighty-nine".