28768521 has 4 divisors (see below), whose sum is σ = 38358032. Its totient is φ = 19179012.

The previous prime is 28768513. The next prime is 28768529. The reversal of 28768521 is 12586782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (28768513) and next prime (28768529).

It is not a de Polignac number, because 28768521 - 2³ = 28768513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28768521.

It is not an unprimeable number, because it can be changed into a prime (28768529) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4794751 + ... + 4794756.

It is an arithmetic number, because the mean of its divisors is an integer number (9589508).

Almost surely, 2^28768521 is an apocalyptic number.

It is an amenable number.

28768521 is a deficient number, since it is larger than the sum of its proper divisors (9589511).

28768521 is an equidigital number, since it uses as much as digits as its factorization.

28768521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9589510.

The product of its digits is 53760, while the sum is 39.

The square root of 28768521 is about 5363.6294614748. The cubic root of 28768521 is about 306.4120532870.

The spelling of 28768521 in words is "twenty-eight million, seven hundred sixty-eight thousand, five hundred twenty-one".