138917605 has 4 divisors (see below), whose sum is σ = 166701132. Its totient is φ = 111134080.

The previous prime is 138917593. The next prime is 138917621. The reversal of 138917605 is 506719831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 97970404 + 40947201 = 9898^2 + 6399^2 .

It is not a de Polignac number, because 138917605 - 2¹⁹ = 138393317 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13891756 + ... + 13891765.

It is an arithmetic number, because the mean of its divisors is an integer number (41675283).

Almost surely, 2^138917605 is an apocalyptic number.

It is an amenable number.

138917605 is a deficient number, since it is larger than the sum of its proper divisors (27783527).

138917605 is an equidigital number, since it uses as much as digits as its factorization.

138917605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27783526.

The product of its (nonzero) digits is 45360, while the sum is 40.

The square root of 138917605 is about 11786.3312782222. The cubic root of 138917605 is about 517.9077729197.

The spelling of 138917605 in words is "one hundred thirty-eight million, nine hundred seventeen thousand, six hundred five".