6881981 has 2 divisors, whose sum is σ = 6881982. Its totient is φ = 6881980.

The previous prime is 6881977. The next prime is 6881989. The reversal of 6881981 is 1891886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5359225 + 1522756 = 2315^2 + 1234^2 .

It is a cyclic number.

It is not a de Polignac number, because 6881981 - 2² = 6881977 is a prime.

It is a super-2 number, since 2×6881981² = 94723324968722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6881989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3440990 + 3440991.

It is an arithmetic number, because the mean of its divisors is an integer number (3440991).

Almost surely, 2^6881981 is an apocalyptic number.

It is an amenable number.

6881981 is a deficient number, since it is larger than the sum of its proper divisors (1).

6881981 is an equidigital number, since it uses as much as digits as its factorization.

6881981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 41.

The square root of 6881981 is about 2623.3530071266. The cubic root of 6881981 is about 190.2119610509.

The spelling of 6881981 in words is "six million, eight hundred eighty-one thousand, nine hundred eighty-one".