408691 has 2 divisors, whose sum is σ = 408692. Its totient is φ = 408690.

The previous prime is 408689. The next prime is 408701. The reversal of 408691 is 196804.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 408691 - 2¹ = 408689 is a prime.

Together with 408689, it forms a pair of twin primes.

408691 is a lucky number.

It is a zygodrome in base 2.

It is not a weakly prime, because it can be changed into another prime (408631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204345 + 204346.

It is an arithmetic number, because the mean of its divisors is an integer number (204346).

2⁴⁰⁸⁶⁹¹ is an apocalyptic number.

408691 is a deficient number, since it is larger than the sum of its proper divisors (1).

408691 is an equidigital number, since it uses as much as digits as its factorization.

408691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 408691 is about 639.2894493107. The cubic root of 408691 is about 74.2104430924.

The spelling of 408691 in words is "four hundred eight thousand, six hundred ninety-one".