408689 has 2 divisors, whose sum is σ = 408690. Its totient is φ = 408688.

The previous prime is 408677. The next prime is 408691. The reversal of 408689 is 986804.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 255025 + 153664 = 505^2 + 392^2 .

It is a cyclic number.

It is not a de Polignac number, because 408689 - 2⁸ = 408433 is a prime.

It is a Sophie Germain prime.

Together with 408691, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 408689.

It is not a weakly prime, because it can be changed into another prime (408659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 204344 + 204345.

It is an arithmetic number, because the mean of its divisors is an integer number (204345).

2⁴⁰⁸⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

408689 is a deficient number, since it is larger than the sum of its proper divisors (1).

408689 is an equidigital number, since it uses as much as digits as its factorization.

408689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 408689 is about 639.2878850721. The cubic root of 408689 is about 74.2103220384.

The spelling of 408689 in words is "four hundred eight thousand, six hundred eighty-nine".