28128861785 has 8 divisors (see below), whose sum is σ = 33800068800. Its totient is φ = 22472799664.

The previous prime is 28128861781. The next prime is 28128861823. The reversal of 28128861785 is 58716882182.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 28128861785 - 2² = 28128861781 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28128861785.

It is not an unprimeable number, because it can be changed into a prime (28128861781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3782135 + ... + 3789564.

It is an arithmetic number, because the mean of its divisors is an integer number (4225008600).

Almost surely, 2^28128861785 is an apocalyptic number.

It is an amenable number.

28128861785 is a deficient number, since it is larger than the sum of its proper divisors (5671207015).

28128861785 is an equidigital number, since it uses as much as digits as its factorization.

28128861785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7572447.

The product of its digits is 3440640, while the sum is 56.

The spelling of 28128861785 in words is "twenty-eight billion, one hundred twenty-eight million, eight hundred sixty-one thousand, seven hundred eighty-five".