404136809 has 2 divisors, whose sum is σ = 404136810. Its totient is φ = 404136808.

The previous prime is 404136797. The next prime is 404136839. The reversal of 404136809 is 908631404.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 401802025 + 2334784 = 20045^2 + 1528^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-404136809 is a prime.

It is not a weakly prime, because it can be changed into another prime (404136839) 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, 202068404 + 202068405.

It is an arithmetic number, because the mean of its divisors is an integer number (202068405).

Almost surely, 2^404136809 is an apocalyptic number.

It is an amenable number.

404136809 is a deficient number, since it is larger than the sum of its proper divisors (1).

404136809 is an equidigital number, since it uses as much as digits as its factorization.

404136809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 404136809 is about 20103.1542052485. The cubic root of 404136809 is about 739.3376158141.

The spelling of 404136809 in words is "four hundred four million, one hundred thirty-six thousand, eight hundred nine".