138666289 has 2 divisors, whose sum is σ = 138666290. Its totient is φ = 138666288.

The previous prime is 138666277. The next prime is 138666293. The reversal of 138666289 is 982666831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129618225 + 9048064 = 11385^2 + 3008^2 .

It is a cyclic number.

It is not a de Polignac number, because 138666289 - 2⁵ = 138666257 is a prime.

It is not a weakly prime, because it can be changed into another prime (138666089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69333144 + 69333145.

It is an arithmetic number, because the mean of its divisors is an integer number (69333145).

Almost surely, 2^138666289 is an apocalyptic number.

It is an amenable number.

138666289 is a deficient number, since it is larger than the sum of its proper divisors (1).

138666289 is an equidigital number, since it uses as much as digits as its factorization.

138666289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 746496, while the sum is 49.

The square root of 138666289 is about 11775.6651192194. The cubic root of 138666289 is about 517.5952685427.

The spelling of 138666289 in words is "one hundred thirty-eight million, six hundred sixty-six thousand, two hundred eighty-nine".