138720 has 72 divisors (see below), whose sum is σ = 464184. Its totient is φ = 34816.

The previous prime is 138683. The next prime is 138727. The reversal of 138720 is 27831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138727) by changing a digit.

138720 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8152 + ... + 8168.

It is an arithmetic number, because the mean of its divisors is an integer number (6447).

2¹³⁸⁷²⁰ is an apocalyptic number.

138720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (232092).

138720 is an abundant number, since it is smaller than the sum of its proper divisors (325464).

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

138720 is a wasteful number, since it uses less digits than its factorization.

138720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 138720 is about 372.4513391035. The cubic root of 138720 is about 51.7662088366.

Subtracting from 138720 its product of nonzero digits (336), we obtain a square (138384 = 372²).

Subtracting from 138720 its reverse (27831), we obtain a square (110889 = 333²).

It can be divided in two parts, 138 and 720, that added together give a palindrome (858).

The spelling of 138720 in words is "one hundred thirty-eight thousand, seven hundred twenty".