2109 has 8 divisors (see below), whose sum is σ = 3040. Its totient is φ = 1296.

The previous prime is 2099. The next prime is 2111. The reversal of 2109 is 9012.

2109 = T₁₇ + T₁₈ + ... + T₂₅.

2109 = 1² + 2² + ... + 18².

It is a happy number.

2109 is nontrivially palindromic in base 15.

2109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2109 - 2⁹ = 1597 is a prime.

It is an alternating number because its digits alternate between even and odd.

2109 is an undulating number in base 15.

It is a Curzon number.

It is a plaindrome in base 12.

It is a nialpdrome in base 13 and base 14.

It is a junction number, because it is equal to n+sod(n) for n = 2094 and 2103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39 + ... + 75.

It is an arithmetic number, because the mean of its divisors is an integer number (380).

It is an amenable number.

2109 is a deficient number, since it is larger than the sum of its proper divisors (931).

2109 is a wasteful number, since it uses less digits than its factorization.

2109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 2109 is about 45.9238500128. The cubic root of 2109 is about 12.8240595657.

Subtracting 2109 from its reverse (9012), we obtain a triangular number (6903 = T₁₁₇).

It can be divided in two parts, 2 and 109, that added together give a palindrome (111).

The spelling of 2109 in words is "two thousand, one hundred nine".