28228521 has 16 divisors (see below), whose sum is σ = 40339584. Its totient is φ = 17512704.

The previous prime is 28228481. The next prime is 28228523. The reversal of 28228521 is 12582282.

It is not a de Polignac number, because 28228521 - 2¹³ = 28220329 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28228523) 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, 2976 + ... + 8081.

It is an arithmetic number, because the mean of its divisors is an integer number (2521224).

Almost surely, 2^28228521 is an apocalyptic number.

It is an amenable number.

28228521 is a deficient number, since it is larger than the sum of its proper divisors (12111063).

28228521 is a wasteful number, since it uses less digits than its factorization.

28228521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11120.

The product of its digits is 5120, while the sum is 30.

The square root of 28228521 is about 5313.0519477980. The cubic root of 28228521 is about 304.4827603409.

The spelling of 28228521 in words is "twenty-eight million, two hundred twenty-eight thousand, five hundred twenty-one".