28528409 has 16 divisors (see below), whose sum is σ = 35280000. Its totient is φ = 22464000.

The previous prime is 28528387. The next prime is 28528421. The reversal of 28528409 is 90482582.

It is not a de Polignac number, because 28528409 - 2²⁴ = 11751193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28528459) 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, 22217 + ... + 23465.

It is an arithmetic number, because the mean of its divisors is an integer number (2205000).

Almost surely, 2^28528409 is an apocalyptic number.

It is an amenable number.

28528409 is a deficient number, since it is larger than the sum of its proper divisors (6751591).

28528409 is a wasteful number, since it uses less digits than its factorization.

28528409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1520.

The product of its (nonzero) digits is 46080, while the sum is 38.

The square root of 28528409 is about 5341.1992099153. The cubic root of 28528409 is about 305.5571969841.

The spelling of 28528409 in words is "twenty-eight million, five hundred twenty-eight thousand, four hundred nine".