185681 has 2 divisors, whose sum is σ = 185682. Its totient is φ = 185680.

The previous prime is 185677. The next prime is 185683. The reversal of 185681 is 186581.

185681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172225 + 13456 = 415^2 + 116^2 .

It is an emirp because it is prime and its reverse (186581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 185681 - 2² = 185677 is a prime.

It is a super-2 number, since 2×185681² = 68954867522, which contains 22 as substring.

Together with 185683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (185683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 92840 + 92841.

It is an arithmetic number, because the mean of its divisors is an integer number (92841).

2¹⁸⁵⁶⁸¹ is an apocalyptic number.

It is an amenable number.

185681 is a deficient number, since it is larger than the sum of its proper divisors (1).

185681 is an equidigital number, since it uses as much as digits as its factorization.

185681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 29.

The square root of 185681 is about 430.9071825811. The cubic root of 185681 is about 57.0500227747.

Subtracting 185681 from its reverse (186581), we obtain a square (900 = 30²).

The spelling of 185681 in words is "one hundred eighty-five thousand, six hundred eighty-one".