28057728109 has 2 divisors, whose sum is σ = 28057728110. Its totient is φ = 28057728108.

The previous prime is 28057728073. The next prime is 28057728121. The reversal of 28057728109 is 90182775082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19118592900 + 8939135209 = 138270^2 + 94547^2 .

It is a cyclic number.

It is not a de Polignac number, because 28057728109 - 2¹⁷ = 28057597037 is a prime.

It is a super-2 number, since 2×28057728109² (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 (28057728409) 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, 14028864054 + 14028864055.

It is an arithmetic number, because the mean of its divisors is an integer number (14028864055).

Almost surely, 2^28057728109 is an apocalyptic number.

It is an amenable number.

28057728109 is a deficient number, since it is larger than the sum of its proper divisors (1).

28057728109 is an equidigital number, since it uses as much as digits as its factorization.

28057728109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 564480, while the sum is 49.

The spelling of 28057728109 in words is "twenty-eight billion, fifty-seven million, seven hundred twenty-eight thousand, one hundred nine".