1320684689 has 2 divisors, whose sum is σ = 1320684690. Its totient is φ = 1320684688.

The previous prime is 1320684649. The next prime is 1320684691. The reversal of 1320684689 is 9864860231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 997296400 + 323388289 = 31580^2 + 17983^2 .

It is an emirp because it is prime and its reverse (9864860231) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1320684689 is a prime.

Together with 1320684691, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1320684619) 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, 660342344 + 660342345.

It is an arithmetic number, because the mean of its divisors is an integer number (660342345).

Almost surely, 2^1320684689 is an apocalyptic number.

It is an amenable number.

1320684689 is a deficient number, since it is larger than the sum of its proper divisors (1).

1320684689 is an equidigital number, since it uses as much as digits as its factorization.

1320684689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 497664, while the sum is 47.

The square root of 1320684689 is about 36341.2257498285. The cubic root of 1320684689 is about 1097.1509436981.

The spelling of 1320684689 in words is "one billion, three hundred twenty million, six hundred eighty-four thousand, six hundred eighty-nine".