28213 has 4 divisors (see below), whose sum is σ = 28620. Its totient is φ = 27808.

The previous prime is 28211. The next prime is 28219. The reversal of 28213 is 31282.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31282 = 2 ⋅15641.

It can be written as a sum of positive squares in 2 ways, for example, as 3249 + 24964 = 57^2 + 158^2 .

It is a cyclic number.

It is not a de Polignac number, because 28213 - 2¹ = 28211 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70 + ... + 247.

It is an arithmetic number, because the mean of its divisors is an integer number (7155).

2²⁸²¹³ is an apocalyptic number.

It is an amenable number.

28213 is a deficient number, since it is larger than the sum of its proper divisors (407).

28213 is an equidigital number, since it uses as much as digits as its factorization.

28213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406.

The product of its digits is 96, while the sum is 16.

The square root of 28213 is about 167.9672587143. The cubic root of 28213 is about 30.4426945121.

Adding to 28213 its reverse (31282), we get a palindrome (59495).

The spelling of 28213 in words is "twenty-eight thousand, two hundred thirteen".