40805 has 4 divisors (see below), whose sum is σ = 48972. Its totient is φ = 32640.

The previous prime is 40801. The next prime is 40813. The reversal of 40805 is 50804.

It is a Cunningham number, because it is equal to 202²+1.

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 14884 + 25921 = 122^2 + 161^2 .

It is not a de Polignac number, because 40805 - 2² = 40801 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40801) 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, 4076 + ... + 4085.

It is an arithmetic number, because the mean of its divisors is an integer number (12243).

2⁴⁰⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

40805 is a deficient number, since it is larger than the sum of its proper divisors (8167).

40805 is an equidigital number, since it uses as much as digits as its factorization.

40805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8166.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 40805 is about 202.0024752324. The cubic root of 40805 is about 34.4274186484.

Subtracting 40805 from its reverse (50804), we obtain a palindrome (9999).

The spelling of 40805 in words is "forty thousand, eight hundred five".