28365685805 has 4 divisors (see below), whose sum is σ = 34038822972. Its totient is φ = 22692548640.

The previous prime is 28365685793. The next prime is 28365685849. The reversal of 28365685805 is 50858656382.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50858656382 = 2 ⋅25429328191.

It can be written as a sum of positive squares in 2 ways, for example, as 7910679364 + 20455006441 = 88942^2 + 143021^2 .

It is not a de Polignac number, because 28365685805 - 2¹² = 28365681709 is a prime.

It is a super-2 number, since 2×28365685805² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2836568576 + ... + 2836568585.

It is an arithmetic number, because the mean of its divisors is an integer number (8509705743).

Almost surely, 2^28365685805 is an apocalyptic number.

It is an amenable number.

28365685805 is a deficient number, since it is larger than the sum of its proper divisors (5673137167).

28365685805 is an equidigital number, since it uses as much as digits as its factorization.

28365685805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5673137166.

The product of its (nonzero) digits is 13824000, while the sum is 56.

The spelling of 28365685805 in words is "twenty-eight billion, three hundred sixty-five million, six hundred eighty-five thousand, eight hundred five".