138240 has 88 divisors (see below), whose sum is σ = 491280. Its totient is φ = 36864.

The previous prime is 138239. The next prime is 138241. The reversal of 138240 is 42831.

It is a happy number.

It is a Jordan-Polya number, since it can be written as 6! ⋅ 4! ⋅ (2!)³.

It is an interprime number because it is at equal distance from previous prime (138239) and next prime (138241).

It is a super-2 number, since 2×138240² = 38220595200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138241) 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, 27646 + ... + 27650.

138240 is a Friedman number, since it can be written as 10*(8+2^4)^3, using all its digits and the basic arithmetic operations.

2¹³⁸²⁴⁰ is an apocalyptic number.

138240 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 138240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (245640).

138240 is an abundant number, since it is smaller than the sum of its proper divisors (353040).

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

138240 is an equidigital number, since it uses as much as digits as its factorization.

138240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34 (or 10 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 138240 is about 371.8064012359. The cubic root of 138240 is about 51.7064325608.

It can be divided in two parts, 138 and 240, that added together give a triangular number (378 = T₂₇).

The spelling of 138240 in words is "one hundred thirty-eight thousand, two hundred forty".