684378534689 has 2 divisors, whose sum is σ = 684378534690. Its totient is φ = 684378534688.

The previous prime is 684378534659. The next prime is 684378534713. The reversal of 684378534689 is 986435873486.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 442368651664 + 242009883025 = 665108^2 + 491945^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684378534689 is a prime.

It is not a weakly prime, because it can be changed into another prime (684378534659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342189267344 + 342189267345.

It is an arithmetic number, because the mean of its divisors is an integer number (342189267345).

Almost surely, 2^684378534689 is an apocalyptic number.

It is an amenable number.

684378534689 is a deficient number, since it is larger than the sum of its proper divisors (1).

684378534689 is an equidigital number, since it uses as much as digits as its factorization.

684378534689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 836075520, while the sum is 71.

The spelling of 684378534689 in words is "six hundred eighty-four billion, three hundred seventy-eight million, five hundred thirty-four thousand, six hundred eighty-nine".