28331 has 4 divisors (see below), whose sum is σ = 29064.
Its totient is φ = 27600.
The previous prime is 28319. The next prime is 28349. The reversal of 28331 is 13382.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13382 = 2 ⋅6691.
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-28331 is a prime.
It is a super-2 number, since 2×283312 = 1605291122, which contains 22 as substring.
It is a Duffinian number.
It is a plaindrome in base 12.
It is a nialpdrome in base 13.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 28331.
It is not an unprimeable number, because it can be changed into a prime (28351) 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, 305 + ... + 386.
It is an arithmetic number, because the mean of its divisors is an integer number (7266).
228331 is an apocalyptic number.
28331 is a deficient number, since it is larger than the sum of its proper divisors (733).
28331 is an equidigital number, since it uses as much as digits as its factorization.
28331 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 732.
The product of its digits is 144, while the sum is 17.
The square root of 28331 is about 168.3181511305.
The cubic root of 28331 is about 30.4850773547.
The spelling of 28331 in words is "twenty-eight thousand, three hundred thirty-one".