138551904 has 96 divisors (see below), whose sum is σ = 427926240. Its totient is φ = 43462656.

The previous prime is 138551869. The next prime is 138551957. The reversal of 138551904 is 409155831.

138551904 is a `hidden beast` number, since 13 + 8 + 551 + 90 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9972 + ... + 19404.

It is an arithmetic number, because the mean of its divisors is an integer number (4457565).

Almost surely, 2^138551904 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 138551904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (213963120).

138551904 is an abundant number, since it is smaller than the sum of its proper divisors (289374336).

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

138551904 is a wasteful number, since it uses less digits than its factorization.

138551904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9469 (or 9455 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 138551904 is about 11770.8072790272. The cubic root of 138551904 is about 517.4529089685.

The spelling of 138551904 in words is "one hundred thirty-eight million, five hundred fifty-one thousand, nine hundred four".