7681 has 2 divisors, whose sum is σ = 7682. Its totient is φ = 7680.

The previous prime is 7673. The next prime is 7687. The reversal of 7681 is 1867.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7056 + 625 = 84^2 + 25^2 .

It is an emirp because it is prime and its reverse (1867) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7681 - 2³ = 7673 is a prime.

It is a super-2 number, since 2×7681² = 117995522, which contains 22 as substring.

It is a nialpdrome in base 6.

It is not a weakly prime, because it can be changed into another prime (7687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3840 + 3841.

It is an arithmetic number, because the mean of its divisors is an integer number (3841).

It is a Proth number, since it is equal to 15 ⋅ 2⁹ + 1 and 15 < 2⁹.

It is an amenable number.

7681 is a deficient number, since it is larger than the sum of its proper divisors (1).

7681 is an equidigital number, since it uses as much as digits as its factorization.

7681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 336, while the sum is 22.

The square root of 7681 is about 87.6413144584. The cubic root of 7681 is about 19.7305528811.

The spelling of 7681 in words is "seven thousand, six hundred eighty-one".