138181 has 2 divisors, whose sum is σ = 138182. Its totient is φ = 138180.

The previous prime is 138179. The next prime is 138191. The reversal of 138181 is 181831.

138181 is digitally balanced in base 2, 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., 133956 + 4225 = 366^2 + 65^2 .

It is a cyclic number.

It is not a de Polignac number, because 138181 - 2¹ = 138179 is a prime.

It is a super-2 number, since 2×138181² = 38187977522, which contains 22 as substring.

Together with 138179, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69090 + 69091.

It is an arithmetic number, because the mean of its divisors is an integer number (69091).

2¹³⁸¹⁸¹ is an apocalyptic number.

It is an amenable number.

138181 is a deficient number, since it is larger than the sum of its proper divisors (1).

138181 is an equidigital number, since it uses as much as digits as its factorization.

138181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192, while the sum is 22.

The square root of 138181 is about 371.7270504012. The cubic root of 138181 is about 51.6990755159.

The spelling of 138181 in words is "one hundred thirty-eight thousand, one hundred eighty-one".