28443678561 has 24 divisors (see below), whose sum is σ = 41724072000. Its totient is φ = 18668412000.

The previous prime is 28443678521. The next prime is 28443678563. The reversal of 28443678561 is 16587634482.

It is a happy number.

28443678561 is a `hidden beast` number, since 2 + 8 + 4 + 4 + 3 + 6 + 78 + 561 = 666.

It is not a de Polignac number, because 28443678561 - 2¹⁵ = 28443645793 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28443678498 and 28443678507.

It is not an unprimeable number, because it can be changed into a prime (28443678563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 416190 + ... + 479688.

It is an arithmetic number, because the mean of its divisors is an integer number (1738503000).

Almost surely, 2^28443678561 is an apocalyptic number.

It is an amenable number.

28443678561 is a deficient number, since it is larger than the sum of its proper divisors (13280393439).

28443678561 is a wasteful number, since it uses less digits than its factorization.

28443678561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64277 (or 64274 counting only the distinct ones).

The product of its digits is 7741440, while the sum is 54.

The spelling of 28443678561 in words is "twenty-eight billion, four hundred forty-three million, six hundred seventy-eight thousand, five hundred sixty-one".