28058209 has 3 divisors (see below), whose sum is σ = 28063507. Its totient is φ = 28052912.

The previous prime is 28058189. The next prime is 28058213. The reversal of 28058209 is 90285082.

The square root of 28058209 is 5297.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 22896225 + 5161984 = 4785^2 + 2272^2 .

It is not a de Polignac number, because 28058209 - 2⁷ = 28058081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28058249) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2649 + ... + 7945.

Almost surely, 2^28058209 is an apocalyptic number.

28058209 is the 5297-th square number.

28058209 is the 2649-th centered octagonal number.

It is an amenable number.

28058209 is a deficient number, since it is larger than the sum of its proper divisors (5298).

28058209 is an frugal number, since it uses more digits than its factorization.

28058209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10594 (or 5297 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 34.

The cubic root of 28058209 is about 303.8691763097.

The spelling of 28058209 in words is "twenty-eight million, fifty-eight thousand, two hundred nine".