28397 has 4 divisors (see below), whose sum is σ = 28860. Its totient is φ = 27936.

The previous prime is 28393. The next prime is 28403. The reversal of 28397 is 79382.

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 11236 + 17161 = 106^2 + 131^2 .

It is a cyclic number.

It is not a de Polignac number, because 28397 - 2² = 28393 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28393) by changing a digit.

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, 122 + ... + 267.

It is an arithmetic number, because the mean of its divisors is an integer number (7215).

2²⁸³⁹⁷ is an apocalyptic number.

It is an amenable number.

28397 is a deficient number, since it is larger than the sum of its proper divisors (463).

28397 is an equidigital number, since it uses as much as digits as its factorization.

28397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 462.

The product of its digits is 3024, while the sum is 29.

The square root of 28397 is about 168.5140943660. The cubic root of 28397 is about 30.5087317112.

The spelling of 28397 in words is "twenty-eight thousand, three hundred ninety-seven".