28819809 has 6 divisors (see below), whose sum is σ = 41628626. Its totient is φ = 19213200.

The previous prime is 28819793. The next prime is 28819829. The reversal of 28819809 is 90891882.

It can be written as a sum of positive squares in only one way, i.e., 26780625 + 2039184 = 5175^2 + 1428^2 .

It is not a de Polignac number, because 28819809 - 2⁴ = 28819793 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28819829) 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 in 5 ways as a sum of consecutive naturals, for example, 1601092 + ... + 1601109.

Almost surely, 2^28819809 is an apocalyptic number.

It is an amenable number.

28819809 is a deficient number, since it is larger than the sum of its proper divisors (12808817).

28819809 is a wasteful number, since it uses less digits than its factorization.

28819809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3202207 (or 3202204 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The square root of 28819809 is about 5368.4084233598. The cubic root of 28819809 is about 306.5940338120.

The spelling of 28819809 in words is "twenty-eight million, eight hundred nineteen thousand, eight hundred nine".