2805 has 16 divisors (see below), whose sum is σ = 5184. Its totient is φ = 1280.

The previous prime is 2803. The next prime is 2819. The reversal of 2805 is 5082.

2805 = T₉ + T₁₀ + ... + T₂₅.

2805 = 12² + 13² + ... + 21².

2805 is nontrivially palindromic in base 2.

It is not a de Polignac number, because 2805 - 2¹ = 2803 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a plaindrome in base 7 and base 13.

It is a nialpdrome in base 5 and base 15.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157 + ... + 173.

It is an arithmetic number, because the mean of its divisors is an integer number (324).

It is an amenable number.

2805 is a deficient number, since it is larger than the sum of its proper divisors (2379).

2805 is a wasteful number, since it uses less digits than its factorization.

2805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 2805 is about 52.9622507075. The cubic root of 2805 is about 14.1029821166.

Adding to 2805 its reverse (5082), we get a palindrome (7887).

The spelling of 2805 in words is "two thousand, eight hundred five".