138908806 has 16 divisors (see below), whose sum is σ = 209892240. Its totient is φ = 68947200.

The previous prime is 138908789. The next prime is 138908807. The reversal of 138908806 is 608809831.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138908807) 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 7 ways as a sum of consecutive naturals, for example, 303730 + ... + 304186.

It is an arithmetic number, because the mean of its divisors is an integer number (13118265).

Almost surely, 2^138908806 is an apocalyptic number.

138908806 is a deficient number, since it is larger than the sum of its proper divisors (70983434).

138908806 is a wasteful number, since it uses less digits than its factorization.

138908806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1239.

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 138908806 is about 11785.9580009433. The cubic root of 138908806 is about 517.8968379805.

The spelling of 138908806 in words is "one hundred thirty-eight million, nine hundred eight thousand, eight hundred six".