4000805 has 4 divisors (see below), whose sum is σ = 4800972. Its totient is φ = 3200640.

The previous prime is 4000751. The next prime is 4000813. The reversal of 4000805 is 5080004.

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 611524 + 3389281 = 782^2 + 1841^2 .

It is not a de Polignac number, because 4000805 - 2⁶ = 4000741 is a prime.

It is a super-3 number, since 3×4000805³ (a number of 21 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400076 + ... + 400085.

It is an arithmetic number, because the mean of its divisors is an integer number (1200243).

Almost surely, 2^4000805 is an apocalyptic number.

It is an amenable number.

4000805 is a deficient number, since it is larger than the sum of its proper divisors (800167).

4000805 is an equidigital number, since it uses as much as digits as its factorization.

4000805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800166.

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

The square root of 4000805 is about 2000.2012398756. The cubic root of 4000805 is about 158.7507532979.

Adding to 4000805 its reverse (5080004), we get a palindrome (9080809).

The spelling of 4000805 in words is "four million, eight hundred five", and thus it is an aban number.