138688717 has 4 divisors (see below), whose sum is σ = 141914080. Its totient is φ = 135463356.

The previous prime is 138688673. The next prime is 138688721. The reversal of 138688717 is 717886831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 138688717 - 2²⁷ = 4470989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138688777) 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 in 3 ways as a sum of consecutive naturals, for example, 1612617 + ... + 1612702.

It is an arithmetic number, because the mean of its divisors is an integer number (35478520).

Almost surely, 2^138688717 is an apocalyptic number.

It is an amenable number.

138688717 is a deficient number, since it is larger than the sum of its proper divisors (3225363).

138688717 is an equidigital number, since it uses as much as digits as its factorization.

138688717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3225362.

The product of its digits is 451584, while the sum is 49.

The square root of 138688717 is about 11776.6173836123. The cubic root of 138688717 is about 517.6231724670.

The spelling of 138688717 in words is "one hundred thirty-eight million, six hundred eighty-eight thousand, seven hundred seventeen".