138688 has 28 divisors (see below), whose sum is σ = 301752. Its totient is φ = 62720.

The previous prime is 138683. The next prime is 138727. The reversal of 138688 is 886831.

It is a super-2 number, since 2×138688² = 38468722688, which contains 22 as substring.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138683) 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, 606 + ... + 802.

2¹³⁸⁶⁸⁸ 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 138688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150876).

138688 is an abundant number, since it is smaller than the sum of its proper divisors (163064).

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

138688 is a wasteful number, since it uses less digits than its factorization.

138688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 210 counting only the distinct ones).

The product of its digits is 9216, while the sum is 34.

The square root of 138688 is about 372.4083779938. The cubic root of 138688 is about 51.7622280454.

The spelling of 138688 in words is "one hundred thirty-eight thousand, six hundred eighty-eight".