28359209 has 4 divisors (see below), whose sum is σ = 28389504. Its totient is φ = 28328916.

The previous prime is 28359181. The next prime is 28359217. The reversal of 28359209 is 90295382.

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 not a de Polignac number, because 28359209 - 2¹⁶ = 28293673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28359239) 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, 13697 + ... + 15630.

It is an arithmetic number, because the mean of its divisors is an integer number (7097376).

Almost surely, 2^28359209 is an apocalyptic number.

It is an amenable number.

28359209 is a deficient number, since it is larger than the sum of its proper divisors (30295).

28359209 is an equidigital number, since it uses as much as digits as its factorization.

28359209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30294.

The product of its (nonzero) digits is 38880, while the sum is 38.

The square root of 28359209 is about 5325.3365151885. The cubic root of 28359209 is about 304.9519193223.

The spelling of 28359209 in words is "twenty-eight million, three hundred fifty-nine thousand, two hundred nine".