28655521 has 4 divisors (see below), whose sum is σ = 28711044. Its totient is φ = 28600000.

The previous prime is 28655503. The next prime is 28655581. The reversal of 28655521 is 12555682.

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 3294225 + 25361296 = 1815^2 + 5036^2 .

It is a cyclic number.

It is not a de Polignac number, because 28655521 - 2⁹ = 28655009 is a prime.

It is a super-2 number, since 2×28655521² = 1642277767562882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28655581) 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, 26980 + ... + 28021.

It is an arithmetic number, because the mean of its divisors is an integer number (7177761).

Almost surely, 2^28655521 is an apocalyptic number.

It is an amenable number.

28655521 is a deficient number, since it is larger than the sum of its proper divisors (55523).

28655521 is an equidigital number, since it uses as much as digits as its factorization.

28655521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55522.

The product of its digits is 24000, while the sum is 34.

The square root of 28655521 is about 5353.0851851993. The cubic root of 28655521 is about 306.0103411146.

The spelling of 28655521 in words is "twenty-eight million, six hundred fifty-five thousand, five hundred twenty-one".