28357106809 has 4 divisors (see below), whose sum is σ = 28467446004. Its totient is φ = 28246767616.

The previous prime is 28357106773. The next prime is 28357106821. The reversal of 28357106809 is 90860175382.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16814827584 + 11542279225 = 129672^2 + 107435^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28357106809 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28357106839) 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 in 3 ways as a sum of consecutive naturals, for example, 55169212 + ... + 55169725.

It is an arithmetic number, because the mean of its divisors is an integer number (7116861501).

Almost surely, 2^28357106809 is an apocalyptic number.

It is an amenable number.

28357106809 is a deficient number, since it is larger than the sum of its proper divisors (110339195).

28357106809 is a wasteful number, since it uses less digits than its factorization.

28357106809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110339194.

The product of its (nonzero) digits is 725760, while the sum is 49.

The spelling of 28357106809 in words is "twenty-eight billion, three hundred fifty-seven million, one hundred six thousand, eight hundred nine".