28520399 has 6 divisors (see below), whose sum is σ = 29142384. Its totient is φ = 27911420.

The previous prime is 28520389. The next prime is 28520417. The reversal of 28520399 is 99302582.

It is not a de Polignac number, because 28520399 - 2⁴ = 28520383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28520329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4247 + ... + 8664.

It is an arithmetic number, because the mean of its divisors is an integer number (4857064).

Almost surely, 2^28520399 is an apocalyptic number.

28520399 is a deficient number, since it is larger than the sum of its proper divisors (621985).

28520399 is an equidigital number, since it uses as much as digits as its factorization.

28520399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13005 (or 12958 counting only the distinct ones).

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

The square root of 28520399 is about 5340.4493256654. The cubic root of 28520399 is about 305.5285969286.

The spelling of 28520399 in words is "twenty-eight million, five hundred twenty thousand, three hundred ninety-nine".