28684409 has 4 divisors (see below), whose sum is σ = 30890916. Its totient is φ = 26477904.

The previous prime is 28684387. The next prime is 28684417. The reversal of 28684409 is 90448682.

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 16933225 + 11751184 = 4115^2 + 3428^2 .

It is a cyclic number.

It is not a de Polignac number, because 28684409 - 2¹⁶ = 28618873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28684009) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1103234 + ... + 1103259.

It is an arithmetic number, because the mean of its divisors is an integer number (7722729).

Almost surely, 2^28684409 is an apocalyptic number.

It is an amenable number.

28684409 is a deficient number, since it is larger than the sum of its proper divisors (2206507).

28684409 is a wasteful number, since it uses less digits than its factorization.

28684409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2206506.

The product of its (nonzero) digits is 110592, while the sum is 41.

The square root of 28684409 is about 5355.7827625848. The cubic root of 28684409 is about 306.1131375684.

The spelling of 28684409 in words is "twenty-eight million, six hundred eighty-four thousand, four hundred nine".