28169 has 4 divisors (see below), whose sum is σ = 29844.
Its totient is φ = 26496.
The previous prime is 28163. The next prime is 28181. The reversal of 28169 is 96182.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96182 = 2 ⋅48091.
It can be written as a sum of positive squares in 2 ways, for example, as 15625 + 12544 = 125^2 + 112^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-28169 is a prime.
It is a super-2 number, since 2×281692 = 1586985122, which contains 22 as substring.
It is an Ulam number.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (28163) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 812 + ... + 845.
It is an arithmetic number, because the mean of its divisors is an integer number (7461).
228169 is an apocalyptic number.
It is an amenable number.
28169 is a deficient number, since it is larger than the sum of its proper divisors (1675).
28169 is a wasteful number, since it uses less digits than its factorization.
28169 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1674.
The product of its digits is 864, while the sum is 26.
The square root of 28169 is about 167.8362297003.
The cubic root of 28169 is about 30.4268604935.
The spelling of 28169 in words is "twenty-eight thousand, one hundred sixty-nine".