6856781 has 2 divisors, whose sum is σ = 6856782. Its totient is φ = 6856780.

The previous prime is 6856771. The next prime is 6856819. The reversal of 6856781 is 1876586.

6856781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6786025 + 70756 = 2605^2 + 266^2 .

It is a cyclic number.

It is not a de Polignac number, because 6856781 - 2¹⁰ = 6855757 is a prime.

It is a super-2 number, since 2×6856781² = 94030891363922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6856771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3428390 + 3428391.

It is an arithmetic number, because the mean of its divisors is an integer number (3428391).

Almost surely, 2^6856781 is an apocalyptic number.

It is an amenable number.

6856781 is a deficient number, since it is larger than the sum of its proper divisors (1).

6856781 is an equidigital number, since it uses as much as digits as its factorization.

6856781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 41.

The square root of 6856781 is about 2618.5455886809. The cubic root of 6856781 is about 189.9795084087.

The spelling of 6856781 in words is "six million, eight hundred fifty-six thousand, seven hundred eighty-one".