8109 has 12 divisors (see below), whose sum is σ = 12636.
Its totient is φ = 4992.
The previous prime is 8101. The next prime is 8111. The reversal of 8109 is 9018.
Subtracting 8109 from its reverse (9018), we obtain a palindrome (909).
8109 = T22 + T23 + ... +
It can be written as a sum of positive squares in 2 ways, for example, as 6084 + 2025 = 78^2 + 45^2
It is not a de Polignac number, because 8109 - 23 = 8101 is a prime.
It is an alternating number because its digits alternate between even and odd.
8109 is a lucky number.
It is a junction number, because it is equal to n+sod(n) for n = 8091 and 8100.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (8101) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 127 + ... + 179.
It is an arithmetic number, because the mean of its divisors is an integer number (1053).
28109 is an apocalyptic number.
It is an amenable number.
8109 is a deficient number, since it is larger than the sum of its proper divisors (4527).
8109 is a wasteful number, since it uses less digits than its factorization.
8109 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 76 (or 73 counting only the distinct ones).
The product of its (nonzero) digits is 72, while the sum is 18.
The square root of 8109 is about 90.0499861188.
The cubic root of 8109 is about 20.0904238932.
The spelling of 8109 in words is "eight thousand, one hundred nine".