28398809 has 2 divisors, whose sum is σ = 28398810. Its totient is φ = 28398808.

The previous prime is 28398781. The next prime is 28398817. The reversal of 28398809 is 90889382.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15054400 + 13344409 = 3880^2 + 3653^2 .

It is a cyclic number.

It is not a de Polignac number, because 28398809 - 2¹⁶ = 28333273 is a prime.

It is not a weakly prime, because it can be changed into another prime (28398829) 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, 14199404 + 14199405.

It is an arithmetic number, because the mean of its divisors is an integer number (14199405).

Almost surely, 2^28398809 is an apocalyptic number.

It is an amenable number.

28398809 is a deficient number, since it is larger than the sum of its proper divisors (1).

28398809 is an equidigital number, since it uses as much as digits as its factorization.

28398809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 47.

The square root of 28398809 is about 5329.0532930343. The cubic root of 28398809 is about 305.0937953933.

The spelling of 28398809 in words is "twenty-eight million, three hundred ninety-eight thousand, eight hundred nine".