138764309 has 2 divisors, whose sum is σ = 138764310. Its totient is φ = 138764308.

The previous prime is 138764291. The next prime is 138764357. The reversal of 138764309 is 903467831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 122036209 + 16728100 = 11047^2 + 4090^2 .

It is a cyclic number.

It is not a de Polignac number, because 138764309 - 2¹² = 138760213 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 (138764389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69382154 + 69382155.

It is an arithmetic number, because the mean of its divisors is an integer number (69382155).

Almost surely, 2^138764309 is an apocalyptic number.

It is an amenable number.

138764309 is a deficient number, since it is larger than the sum of its proper divisors (1).

138764309 is an equidigital number, since it uses as much as digits as its factorization.

138764309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 138764309 is about 11779.8263569545. The cubic root of 138764309 is about 517.7171985347.

The spelling of 138764309 in words is "one hundred thirty-eight million, seven hundred sixty-four thousand, three hundred nine".