28488557 has 4 divisors (see below), whose sum is σ = 29258556. Its totient is φ = 27718560.

The previous prime is 28488547. The next prime is 28488569. The reversal of 28488557 is 75588482.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75588482 = 2 ⋅37794241.

It can be written as a sum of positive squares in 2 ways, for example, as 18369796 + 10118761 = 4286^2 + 3181^2 .

It is a cyclic number.

It is not a de Polignac number, because 28488557 - 2⁴ = 28488541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28488517) 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, 384944 + ... + 385017.

It is an arithmetic number, because the mean of its divisors is an integer number (7314639).

Almost surely, 2^28488557 is an apocalyptic number.

It is an amenable number.

28488557 is a deficient number, since it is larger than the sum of its proper divisors (769999).

28488557 is an equidigital number, since it uses as much as digits as its factorization.

28488557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769998.

The product of its digits is 716800, while the sum is 47.

The square root of 28488557 is about 5337.4672832721. The cubic root of 28488557 is about 305.4148506892.

The spelling of 28488557 in words is "twenty-eight million, four hundred eighty-eight thousand, five hundred fifty-seven".