2605 has 4 divisors (see below), whose sum is σ = 3132.
Its totient is φ = 2080.
The previous prime is 2593. The next prime is 2609. The reversal of 2605 is 5062.
Adding to 2605 its reverse (5062), we get a palindrome (7667).
2605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5062 = 2 ⋅2531.
It can be written as a sum of positive squares in 2 ways, for example, as 841 + 1764 = 29^2 + 42^2
It is not a de Polignac number, because 2605 - 27 = 2477 is a prime.
It is a Smith number, since the sum of its digits (13) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.
It is a Duffinian number.
It is a plaindrome in base 13.
It is a nialpdrome in base 14.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (2609) 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, 256 + ... + 265.
It is an arithmetic number, because the mean of its divisors is an integer number (783).
22605 is an apocalyptic number.
It is an amenable number.
2605 is a deficient number, since it is larger than the sum of its proper divisors (527).
2605 is an equidigital number, since it uses as much as digits as its factorization.
2605 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 526.
The product of its (nonzero) digits is 60, while the sum is 13.
The square root of 2605 is about 51.0392006207.
The cubic root of 2605 is about 13.7594975704.
The spelling of 2605 in words is "two thousand, six hundred five".