684328409 has 4 divisors (see below), whose sum is σ = 684408804. Its totient is φ = 684248016.

The previous prime is 684328391. The next prime is 684328423. The reversal of 684328409 is 904823486.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 407838025 + 276490384 = 20195^2 + 16628^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684328409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 684328409.

It is not an unprimeable number, because it can be changed into a prime (684328009) 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 in 3 ways as a sum of consecutive naturals, for example, 25682 + ... + 45035.

It is an arithmetic number, because the mean of its divisors is an integer number (171102201).

Almost surely, 2^684328409 is an apocalyptic number.

It is an amenable number.

684328409 is a deficient number, since it is larger than the sum of its proper divisors (80395).

684328409 is an equidigital number, since it uses as much as digits as its factorization.

684328409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80394.

The product of its (nonzero) digits is 331776, while the sum is 44.

The square root of 684328409 is about 26159.6714237775. The cubic root of 684328409 is about 881.2278010336.

The spelling of 684328409 in words is "six hundred eighty-four million, three hundred twenty-eight thousand, four hundred nine".