28807209 has 6 divisors (see below), whose sum is σ = 41610426. Its totient is φ = 19204800.

The previous prime is 28807183. The next prime is 28807217. The reversal of 28807209 is 90270882.

It can be written as a sum of positive squares in only one way, i.e., 28355625 + 451584 = 5325^2 + 672^2 .

It is not a de Polignac number, because 28807209 - 2⁷ = 28807081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28807279) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1600392 + ... + 1600409.

It is an arithmetic number, because the mean of its divisors is an integer number (6935071).

Almost surely, 2^28807209 is an apocalyptic number.

It is an amenable number.

28807209 is a deficient number, since it is larger than the sum of its proper divisors (12803217).

28807209 is a wasteful number, since it uses less digits than its factorization.

28807209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3200807 (or 3200804 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 28807209 is about 5367.2347628923. The cubic root of 28807209 is about 306.5493464011.

The spelling of 28807209 in words is "twenty-eight million, eight hundred seven thousand, two hundred nine".