4009591 has 4 divisors (see below), whose sum is σ = 4075384. Its totient is φ = 3943800.

The previous prime is 4009549. The next prime is 4009619. The reversal of 4009591 is 1959004.

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

It is a cyclic number.

It is not a de Polignac number, because 4009591 - 2¹³ = 4001399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4009531) 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, 32805 + ... + 32926.

It is an arithmetic number, because the mean of its divisors is an integer number (1018846).

Almost surely, 2^4009591 is an apocalyptic number.

4009591 is a deficient number, since it is larger than the sum of its proper divisors (65793).

4009591 is an equidigital number, since it uses as much as digits as its factorization.

4009591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65792.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 4009591 is about 2002.3963144193. The cubic root of 4009591 is about 158.8668769575.

It can be divided in two parts, 400959 and 1, that added together give a triangular number (400960 = T₈₉₅).

The spelling of 4009591 in words is "four million, nine thousand, five hundred ninety-one".