28520515 has 4 divisors (see below), whose sum is σ = 34224624. Its totient is φ = 22816408.

The previous prime is 28520491. The next prime is 28520521. The reversal of 28520515 is 51502582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51502582 = 2 ⋅25751291.

It is a cyclic number.

It is not a de Polignac number, because 28520515 - 2⁹ = 28520003 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2852047 + ... + 2852056.

It is an arithmetic number, because the mean of its divisors is an integer number (8556156).

Almost surely, 2^28520515 is an apocalyptic number.

28520515 is a deficient number, since it is larger than the sum of its proper divisors (5704109).

28520515 is an equidigital number, since it uses as much as digits as its factorization.

28520515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5704108.

The product of its (nonzero) digits is 4000, while the sum is 28.

The square root of 28520515 is about 5340.4601861637. The cubic root of 28520515 is about 305.5290111499.

The spelling of 28520515 in words is "twenty-eight million, five hundred twenty thousand, five hundred fifteen".