28380685 has 4 divisors (see below), whose sum is σ = 34056828. Its totient is φ = 22704544.

The previous prime is 28380673. The next prime is 28380707. The reversal of 28380685 is 58608382.

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 6869641 + 21511044 = 2621^2 + 4638^2 .

It is a cyclic number.

It is not a de Polignac number, because 28380685 - 2⁷ = 28380557 is a prime.

It is a Smith number, since the sum of its digits (40) 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 a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2838064 + ... + 2838073.

It is an arithmetic number, because the mean of its divisors is an integer number (8514207).

Almost surely, 2^28380685 is an apocalyptic number.

It is an amenable number.

28380685 is a deficient number, since it is larger than the sum of its proper divisors (5676143).

28380685 is an equidigital number, since it uses as much as digits as its factorization.

28380685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5676142.

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 28380685 is about 5327.3525319806. The cubic root of 28380685 is about 305.0288783908.

The spelling of 28380685 in words is "twenty-eight million, three hundred eighty thousand, six hundred eighty-five".