138533904 has 30 divisors (see below), whose sum is σ = 387702926. Its totient is φ = 46177920.

The previous prime is 138533881. The next prime is 138533909. The reversal of 138533904 is 409335831.

138533904 is a `hidden beast` number, since 1 + 38 + 533 + 90 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 138015504 + 518400 = 11748^2 + 720^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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 (138533909) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 480877 + ... + 481164.

Almost surely, 2^138533904 is an apocalyptic number.

It is an amenable number.

138533904 is an abundant number, since it is smaller than the sum of its proper divisors (249169022).

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

138533904 is a wasteful number, since it uses less digits than its factorization.

138533904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 962055 (or 962046 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 138533904 is about 11770.0426507299. The cubic root of 138533904 is about 517.4304996632.

The spelling of 138533904 in words is "one hundred thirty-eight million, five hundred thirty-three thousand, nine hundred four".