6686681 has 2 divisors, whose sum is σ = 6686682. Its totient is φ = 6686680.

The previous prime is 6686663. The next prime is 6686699. The reversal of 6686681 is 1866866.

It is a balanced prime because it is at equal distance from previous prime (6686663) and next prime (6686699).

It can be written as a sum of positive squares in only one way, i.e., 6046681 + 640000 = 2459^2 + 800^2 .

It is a cyclic number.

It is not a de Polignac number, because 6686681 - 2¹⁴ = 6670297 is a prime.

It is a super-2 number, since 2×6686681² = 89423405591522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (6686611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3343340 + 3343341.

It is an arithmetic number, because the mean of its divisors is an integer number (3343341).

Almost surely, 2^6686681 is an apocalyptic number.

It is an amenable number.

6686681 is a deficient number, since it is larger than the sum of its proper divisors (1).

6686681 is an equidigital number, since it uses as much as digits as its factorization.

6686681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 41.

The square root of 6686681 is about 2585.8617519117. The cubic root of 6686681 is about 188.3953597005.

The spelling of 6686681 in words is "six million, six hundred eighty-six thousand, six hundred eighty-one".