138404 has 12 divisors (see below), whose sum is σ = 276864. Its totient is φ = 59304.

The previous prime is 138403. The next prime is 138407. The reversal of 138404 is 404831.

138404 = T₁₈₂ + T₁₈₃ + ... + T₁₈₉.

138404 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138401) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2444 + ... + 2499.

It is an arithmetic number, because the mean of its divisors is an integer number (23072).

2¹³⁸⁴⁰⁴ is an apocalyptic number.

138404 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

138404 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

138404 is a wasteful number, since it uses less digits than its factorization.

138404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4954 (or 4952 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 138404 is about 372.0268807492. The cubic root of 138404 is about 51.7268716614.

Subtracting from 138404 its sum of digits (20), we obtain a square (138384 = 372²).

The spelling of 138404 in words is "one hundred thirty-eight thousand, four hundred four".