28889809 has 4 divisors (see below), whose sum is σ = 31112116. Its totient is φ = 26667504.

The previous prime is 28889803. The next prime is 28889827. The reversal of 28889809 is 90898882.

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 12446784 + 16443025 = 3528^2 + 4055^2 .

It is a cyclic number.

It is not a de Polignac number, because 28889809 - 2¹³ = 28881617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28889803) 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 3 ways as a sum of consecutive naturals, for example, 1111134 + ... + 1111159.

It is an arithmetic number, because the mean of its divisors is an integer number (7778029).

Almost surely, 2^28889809 is an apocalyptic number.

It is an amenable number.

28889809 is a deficient number, since it is larger than the sum of its proper divisors (2222307).

28889809 is a wasteful number, since it uses less digits than its factorization.

28889809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2222306.

The product of its (nonzero) digits is 663552, while the sum is 52.

The square root of 28889809 is about 5374.9240924873. The cubic root of 28889809 is about 306.8420603212.

The spelling of 28889809 in words is "twenty-eight million, eight hundred eighty-nine thousand, eight hundred nine".