28755521 has 4 divisors (see below), whose sum is σ = 29298132. Its totient is φ = 28212912.

The previous prime is 28755511. The next prime is 28755527. The reversal of 28755521 is 12555782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21492496 + 7263025 = 4636^2 + 2695^2 .

It is a cyclic number.

It is not a de Polignac number, because 28755521 - 2⁶ = 28755457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28755527) 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, 271226 + ... + 271331.

It is an arithmetic number, because the mean of its divisors is an integer number (7324533).

Almost surely, 2^28755521 is an apocalyptic number.

It is an amenable number.

28755521 is a deficient number, since it is larger than the sum of its proper divisors (542611).

28755521 is an equidigital number, since it uses as much as digits as its factorization.

28755521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542610.

The product of its digits is 28000, while the sum is 35.

The square root of 28755521 is about 5362.4174585722. The cubic root of 28755521 is about 306.3658922203.

The spelling of 28755521 in words is "twenty-eight million, seven hundred fifty-five thousand, five hundred twenty-one".