138966018181 has 4 divisors (see below), whose sum is σ = 139172506252. Its totient is φ = 138759530112.

The previous prime is 138966018151. The next prime is 138966018241. The reversal of 138966018181 is 181810669831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 181810669831 = 7 ⋅25972952833.

It can be written as a sum of positive squares in 2 ways, for example, as 52961657956 + 86004360225 = 230134^2 + 293265^2 .

It is a cyclic number.

It is not a de Polignac number, because 138966018181 - 2⁹ = 138966017669 is a prime.

It is a super-2 number, since 2×138966018181² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138966018151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103243026 + ... + 103244371.

It is an arithmetic number, because the mean of its divisors is an integer number (34793126563).

Almost surely, 2^138966018181 is an apocalyptic number.

It is an amenable number.

138966018181 is a deficient number, since it is larger than the sum of its proper divisors (206488071).

138966018181 is an equidigital number, since it uses as much as digits as its factorization.

138966018181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206488070.

The product of its (nonzero) digits is 497664, while the sum is 52.

The spelling of 138966018181 in words is "one hundred thirty-eight billion, nine hundred sixty-six million, eighteen thousand, one hundred eighty-one".