138865207181 has 2 divisors, whose sum is σ = 138865207182. Its totient is φ = 138865207180.

The previous prime is 138865207177. The next prime is 138865207237. The reversal of 138865207181 is 181702568831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 83703169225 + 55162037956 = 289315^2 + 234866^2 .

It is a cyclic number.

It is not a de Polignac number, because 138865207181 - 2² = 138865207177 is a prime.

It is a super-2 number, since 2×138865207181² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138865207121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69432603590 + 69432603591.

It is an arithmetic number, because the mean of its divisors is an integer number (69432603591).

Almost surely, 2^138865207181 is an apocalyptic number.

It is an amenable number.

138865207181 is a deficient number, since it is larger than the sum of its proper divisors (1).

138865207181 is an equidigital number, since it uses as much as digits as its factorization.

138865207181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 645120, while the sum is 50.

The spelling of 138865207181 in words is "one hundred thirty-eight billion, eight hundred sixty-five million, two hundred seven thousand, one hundred eighty-one".