28185457805 has 4 divisors (see below), whose sum is σ = 33822549372. Its totient is φ = 22548366240.

The previous prime is 28185457789. The next prime is 28185457829. The reversal of 28185457805 is 50875458182.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50875458182 = 2 ⋅25437729091.

It can be written as a sum of positive squares in 2 ways, for example, as 13780177321 + 14405280484 = 117389^2 + 120022^2 .

It is not a de Polignac number, because 28185457805 - 2⁴ = 28185457789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2818545776 + ... + 2818545785.

It is an arithmetic number, because the mean of its divisors is an integer number (8455637343).

Almost surely, 2^28185457805 is an apocalyptic number.

It is an amenable number.

28185457805 is a deficient number, since it is larger than the sum of its proper divisors (5637091567).

28185457805 is an equidigital number, since it uses as much as digits as its factorization.

28185457805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5637091566.

The product of its (nonzero) digits is 3584000, while the sum is 53.

The spelling of 28185457805 in words is "twenty-eight billion, one hundred eighty-five million, four hundred fifty-seven thousand, eight hundred five".