28618609 has 4 divisors (see below), whose sum is σ = 29021760. Its totient is φ = 28215460.

The previous prime is 28618559. The next prime is 28618631. The reversal of 28618609 is 90681682.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28618609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28619609) 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, 201469 + ... + 201610.

It is an arithmetic number, because the mean of its divisors is an integer number (7255440).

Almost surely, 2^28618609 is an apocalyptic number.

It is an amenable number.

28618609 is a deficient number, since it is larger than the sum of its proper divisors (403151).

28618609 is an equidigital number, since it uses as much as digits as its factorization.

28618609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403150.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 28618609 is about 5349.6363427807. The cubic root of 28618609 is about 305.8788910858.

The spelling of 28618609 in words is "twenty-eight million, six hundred eighteen thousand, six hundred nine".