138866873 has 2 divisors, whose sum is σ = 138866874. Its totient is φ = 138866872.

The previous prime is 138866869. The next prime is 138866879. The reversal of 138866873 is 378668831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 134490409 + 4376464 = 11597^2 + 2092^2 .

It is an emirp because it is prime and its reverse (378668831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138866873 - 2² = 138866869 is a prime.

It is not a weakly prime, because it can be changed into another prime (138866879) 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, 69433436 + 69433437.

It is an arithmetic number, because the mean of its divisors is an integer number (69433437).

Almost surely, 2^138866873 is an apocalyptic number.

It is an amenable number.

138866873 is a deficient number, since it is larger than the sum of its proper divisors (1).

138866873 is an equidigital number, since it uses as much as digits as its factorization.

138866873 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1161216, while the sum is 50.

The square root of 138866873 is about 11784.1789276979. The cubic root of 138866873 is about 517.8447194854.

The spelling of 138866873 in words is "one hundred thirty-eight million, eight hundred sixty-six thousand, eight hundred seventy-three".