28812209 has 2 divisors, whose sum is σ = 28812210. Its totient is φ = 28812208.

The previous prime is 28812181. The next prime is 28812247. The reversal of 28812209 is 90221882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18731584 + 10080625 = 4328^2 + 3175^2 .

It is a cyclic number.

It is not a de Polignac number, because 28812209 - 2⁸ = 28811953 is a prime.

It is not a weakly prime, because it can be changed into another prime (28812409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14406104 + 14406105.

It is an arithmetic number, because the mean of its divisors is an integer number (14406105).

Almost surely, 2^28812209 is an apocalyptic number.

It is an amenable number.

28812209 is a deficient number, since it is larger than the sum of its proper divisors (1).

28812209 is an equidigital number, since it uses as much as digits as its factorization.

28812209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 28812209 is about 5367.7005318851. The cubic root of 28812209 is about 306.5670810598.

The spelling of 28812209 in words is "twenty-eight million, eight hundred twelve thousand, two hundred nine".