28856209 has 2 divisors, whose sum is σ = 28856210. Its totient is φ = 28856208.

The previous prime is 28856197. The next prime is 28856273. The reversal of 28856209 is 90265882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16974400 + 11881809 = 4120^2 + 3447^2 .

It is a cyclic number.

It is not a de Polignac number, because 28856209 - 2¹⁵ = 28823441 is a prime.

It is a super-4 number, since 4×28856209⁴ (a number of 31 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is not a weakly prime, because it can be changed into another prime (28856279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14428104 + 14428105.

It is an arithmetic number, because the mean of its divisors is an integer number (14428105).

Almost surely, 2^28856209 is an apocalyptic number.

It is an amenable number.

28856209 is a deficient number, since it is larger than the sum of its proper divisors (1).

28856209 is an equidigital number, since it uses as much as digits as its factorization.

28856209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 28856209 is about 5371.7975576151. The cubic root of 28856209 is about 306.7230576567.

The spelling of 28856209 in words is "twenty-eight million, eight hundred fifty-six thousand, two hundred nine".