405491 has 2 divisors, whose sum is σ = 405492. Its totient is φ = 405490.

The previous prime is 405487. The next prime is 405497. The reversal of 405491 is 194504.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 405491 - 2² = 405487 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 405491.

It is not a weakly prime, because it can be changed into another prime (405497) 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, 202745 + 202746.

It is an arithmetic number, because the mean of its divisors is an integer number (202746).

2⁴⁰⁵⁴⁹¹ is an apocalyptic number.

405491 is a deficient number, since it is larger than the sum of its proper divisors (1).

405491 is an equidigital number, since it uses as much as digits as its factorization.

405491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 405491 is about 636.7817522511. The cubic root of 405491 is about 74.0162491709.

Adding to 405491 its reverse (194504), we get a palindrome (599995).

The spelling of 405491 in words is "four hundred five thousand, four hundred ninety-one".