28509861601 has 8 divisors (see below), whose sum is σ = 31282229160. Its totient is φ = 25820251392.

The previous prime is 28509861571. The next prime is 28509861629. The reversal of 28509861601 is 10616890582.

It can be written as a sum of positive squares in 4 ways, for example, as 9189139600 + 19320722001 = 95860^2 + 138999^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28509861601 - 2⁹ = 28509861089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28509868601) 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 7 ways as a sum of consecutive naturals, for example, 20688616 + ... + 20689993.

It is an arithmetic number, because the mean of its divisors is an integer number (3910278645).

Almost surely, 2^28509861601 is an apocalyptic number.

It is an amenable number.

28509861601 is a deficient number, since it is larger than the sum of its proper divisors (2772367559).

28509861601 is a wasteful number, since it uses less digits than its factorization.

28509861601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41378675.

The product of its (nonzero) digits is 207360, while the sum is 46.

The spelling of 28509861601 in words is "twenty-eight billion, five hundred nine million, eight hundred sixty-one thousand, six hundred one".