28056444781 has 2 divisors, whose sum is σ = 28056444782. Its totient is φ = 28056444780.

The previous prime is 28056444749. The next prime is 28056444827. The reversal of 28056444781 is 18744465082.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26539342281 + 1517102500 = 162909^2 + 38950^2 .

It is a cyclic number.

It is not a de Polignac number, because 28056444781 - 2⁵ = 28056444749 is a prime.

It is a super-2 number, since 2×28056444781² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28056447781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14028222390 + 14028222391.

It is an arithmetic number, because the mean of its divisors is an integer number (14028222391).

Almost surely, 2^28056444781 is an apocalyptic number.

It is an amenable number.

28056444781 is a deficient number, since it is larger than the sum of its proper divisors (1).

28056444781 is an equidigital number, since it uses as much as digits as its factorization.

28056444781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1720320, while the sum is 49.

The spelling of 28056444781 in words is "twenty-eight billion, fifty-six million, four hundred forty-four thousand, seven hundred eighty-one".