138911904 has 144 divisors (see below), whose sum is σ = 419694912. Its totient is φ = 43490304.

The previous prime is 138911893. The next prime is 138911909. The reversal of 138911904 is 409119831.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (138911909) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 443652 + ... + 443964.

It is an arithmetic number, because the mean of its divisors is an integer number (2914548).

Almost surely, 2^138911904 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 138911904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (209847456).

138911904 is an abundant number, since it is smaller than the sum of its proper divisors (280783008).

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

138911904 is a wasteful number, since it uses less digits than its factorization.

138911904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419 (or 408 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 138911904 is about 11786.0894277958. The cubic root of 138911904 is about 517.9006880663.

The spelling of 138911904 in words is "one hundred thirty-eight million, nine hundred eleven thousand, nine hundred four".