4005840 has 40 divisors (see below), whose sum is σ = 12418848. Its totient is φ = 1068160.

The previous prime is 4005839. The next prime is 4005847. The reversal of 4005840 is 485004.

It is a tau number, because it is divible by the number of its divisors (40).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4005847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8106 + ... + 8585.

Almost surely, 2^4005840 is an apocalyptic number.

4005840 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

4005840 is an abundant number, since it is smaller than the sum of its proper divisors (8413008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

4005840 is a wasteful number, since it uses less digits than its factorization.

4005840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16707 (or 16701 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 21.

The square root of 4005840 is about 2001.4594674887. The cubic root of 4005840 is about 158.8173211484.

The spelling of 4005840 in words is "four million, five thousand, eight hundred forty".