28320405 has 16 divisors (see below), whose sum is σ = 45451584. Its totient is φ = 15057920.

The previous prime is 28320403. The next prime is 28320407. The reversal of 28320405 is 50402382.

It is an interprime number because it is at equal distance from previous prime (28320403) and next prime (28320407).

It is not a de Polignac number, because 28320405 - 2¹ = 28320403 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28320403) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2485 + ... + 7925.

It is an arithmetic number, because the mean of its divisors is an integer number (2840724).

Almost surely, 2^28320405 is an apocalyptic number.

It is an amenable number.

28320405 is a deficient number, since it is larger than the sum of its proper divisors (17131179).

28320405 is a wasteful number, since it uses less digits than its factorization.

28320405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5796.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 28320405 is about 5321.6919302042. The cubic root of 28320405 is about 304.8127669269.

Adding to 28320405 its reverse (50402382), we get a palindrome (78722787).

The spelling of 28320405 in words is "twenty-eight million, three hundred twenty thousand, four hundred five".