4090391 has 4 divisors (see below), whose sum is σ = 4096800. Its totient is φ = 4083984.

The previous prime is 4090379. The next prime is 4090397. The reversal of 4090391 is 1930904.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4090391 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4090391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4090397) 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 3 ways as a sum of consecutive naturals, for example, 2126 + ... + 3563.

It is an arithmetic number, because the mean of its divisors is an integer number (1024200).

Almost surely, 2^4090391 is an apocalyptic number.

4090391 is a deficient number, since it is larger than the sum of its proper divisors (6409).

4090391 is an equidigital number, since it uses as much as digits as its factorization.

4090391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6408.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 4090391 is about 2022.4715078339. The cubic root of 4090391 is about 159.9269327833.

The spelling of 4090391 in words is "four million, ninety thousand, three hundred ninety-one".