6856849661 has 2 divisors, whose sum is σ = 6856849662. Its totient is φ = 6856849660.

The previous prime is 6856849633. The next prime is 6856849663. The reversal of 6856849661 is 1669486586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6196051225 + 660798436 = 78715^2 + 25706^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6856849661 is a prime.

Together with 6856849663, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6856849661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6856849663) 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, 3428424830 + 3428424831.

It is an arithmetic number, because the mean of its divisors is an integer number (3428424831).

Almost surely, 2^6856849661 is an apocalyptic number.

It is an amenable number.

6856849661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6856849661 is an equidigital number, since it uses as much as digits as its factorization.

6856849661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14929920, while the sum is 59.

The square root of 6856849661 is about 82806.0967622554. The cubic root of 6856849661 is about 1899.8014253228.

The spelling of 6856849661 in words is "six billion, eight hundred fifty-six million, eight hundred forty-nine thousand, six hundred sixty-one".