28188609 has 16 divisors (see below), whose sum is σ = 40929600. Its totient is φ = 17188416.

The previous prime is 28188583. The next prime is 28188613. The reversal of 28188609 is 90688182.

28188609 = 318² + 319² + ... + 488².

It is not a de Polignac number, because 28188609 - 2²⁰ = 27140033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28188619) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6874 + ... + 10179.

It is an arithmetic number, because the mean of its divisors is an integer number (2558100).

Almost surely, 2^28188609 is an apocalyptic number.

28188609 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

28188609 is a deficient number, since it is larger than the sum of its proper divisors (12740991).

28188609 is a wasteful number, since it uses less digits than its factorization.

28188609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17104.

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 28188609 is about 5309.2945859125. The cubic root of 28188609 is about 304.3391910307.

The spelling of 28188609 in words is "twenty-eight million, one hundred eighty-eight thousand, six hundred nine".