138691251709 has 2 divisors, whose sum is σ = 138691251710. Its totient is φ = 138691251708.

The previous prime is 138691251689. The next prime is 138691251749. The reversal of 138691251709 is 907152196831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134245296025 + 4445955684 = 366395^2 + 66678^2 .

It is a cyclic number.

It is not a de Polignac number, because 138691251709 - 2⁹ = 138691251197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138691251749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69345625854 + 69345625855.

It is an arithmetic number, because the mean of its divisors is an integer number (69345625855).

Almost surely, 2^138691251709 is an apocalyptic number.

It is an amenable number.

138691251709 is a deficient number, since it is larger than the sum of its proper divisors (1).

138691251709 is an equidigital number, since it uses as much as digits as its factorization.

138691251709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 816480, while the sum is 52.

The spelling of 138691251709 in words is "one hundred thirty-eight billion, six hundred ninety-one million, two hundred fifty-one thousand, seven hundred nine".