2005 has 4 divisors (see below), whose sum is σ = 2412. Its totient is φ = 1600.

The previous prime is 2003. The next prime is 2011. The reversal of 2005 is 5002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1521 + 484 = 39^2 + 22^2 .

It is a sliding number, since 2005 = 5 + 2000 and 1/5 + 1/2000 = 0.2005.

It is not a de Polignac number, because 2005 - 2¹ = 2003 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a nialpdrome in base 13 and base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2003) 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, 196 + ... + 205.

It is an arithmetic number, because the mean of its divisors is an integer number (603).

2²⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

2005 is a deficient number, since it is larger than the sum of its proper divisors (407).

2005 is an equidigital number, since it uses as much as digits as its factorization.

2005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406.

The product of its (nonzero) digits is 10, while the sum is 7.

The square root of 2005 is about 44.7772263545. Note that the first 3 decimals coincide. The cubic root of 2005 is about 12.6097011037.

Adding to 2005 its reverse (5002), we get a palindrome (7007).

It can be divided in two parts, 200 and 5, that multiplied together give a cube (1000 = 10³).

The spelling of 2005 in words is "two thousand, five".