404240509 has 2 divisors, whose sum is σ = 404240510. Its totient is φ = 404240508.

The previous prime is 404240497. The next prime is 404240539. The reversal of 404240509 is 905042404.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 318622500 + 85618009 = 17850^2 + 9253^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-404240509 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (404240539) 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 as a sum of consecutive naturals, namely, 202120254 + 202120255.

It is an arithmetic number, because the mean of its divisors is an integer number (202120255).

Almost surely, 2^404240509 is an apocalyptic number.

It is an amenable number.

404240509 is a deficient number, since it is larger than the sum of its proper divisors (1).

404240509 is an equidigital number, since it uses as much as digits as its factorization.

404240509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 404240509 is about 20105.7332370645. The cubic root of 404240509 is about 739.4008474989.

It can be divided in two parts, 4042 and 40509, that added together give a triangular number (44551 = T₂₉₈).

The spelling of 404240509 in words is "four hundred four million, two hundred forty thousand, five hundred nine".