138680309 has 2 divisors, whose sum is σ = 138680310. Its totient is φ = 138680308.

The previous prime is 138680303. The next prime is 138680323. The reversal of 138680309 is 903086831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116165284 + 22515025 = 10778^2 + 4745^2 .

It is a cyclic number.

It is not a de Polignac number, because 138680309 - 2⁴ = 138680293 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138680303) 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 as a sum of consecutive naturals, namely, 69340154 + 69340155.

It is an arithmetic number, because the mean of its divisors is an integer number (69340155).

Almost surely, 2^138680309 is an apocalyptic number.

It is an amenable number.

138680309 is a deficient number, since it is larger than the sum of its proper divisors (1).

138680309 is an equidigital number, since it uses as much as digits as its factorization.

138680309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 138680309 is about 11776.2603996345. The cubic root of 138680309 is about 517.6127119583.

The spelling of 138680309 in words is "one hundred thirty-eight million, six hundred eighty thousand, three hundred nine".