138424 has 32 divisors (see below), whose sum is σ = 307440. Its totient is φ = 58080.

The previous prime is 138407. The next prime is 138427. The reversal of 138424 is 424831.

138424 = T₆₄ + T₆₅ + ... + T₁₀₂.

It is a super-2 number, since 2×138424² = 38322407552, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a nialpdrome in base 11.

It is a junction number, because it is equal to n+sod(n) for n = 138395 and 138404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10642 + ... + 10654.

2¹³⁸⁴²⁴ 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 138424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153720).

138424 is an abundant number, since it is smaller than the sum of its proper divisors (169016).

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

138424 is a wasteful number, since it uses less digits than its factorization.

138424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52 (or 26 counting only the distinct ones).

The product of its digits is 768, while the sum is 22.

The square root of 138424 is about 372.0537595563. The cubic root of 138424 is about 51.7293631299.

The spelling of 138424 in words is "one hundred thirty-eight thousand, four hundred twenty-four".