138640008 has 64 divisors (see below), whose sum is σ = 374391360. Its totient is φ = 42529536.

The previous prime is 138640003. The next prime is 138640009. The reversal of 138640008 is 800046831.

It is a happy number.

138640008 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×138640008³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (138640001) 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 15 ways as a sum of consecutive naturals, for example, 182766 + ... + 183522.

It is an arithmetic number, because the mean of its divisors is an integer number (5849865).

Almost surely, 2^138640008 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138640008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (187195680).

138640008 is an abundant number, since it is smaller than the sum of its proper divisors (235751352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138640008 is a wasteful number, since it uses less digits than its factorization.

138640008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366 (or 1362 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 138640008 is about 11774.5491633438. The cubic root of 138640008 is about 517.5625670577.

Adding to 138640008 its reverse (800046831), we get a palindrome (938686839).

It can be divided in two parts, 138 and 640008, that added together give a triangular number (640146 = T₁₁₃₁).

The spelling of 138640008 in words is "one hundred thirty-eight million, six hundred forty thousand, eight".