138394240 has 64 divisors (see below), whose sum is σ = 334280520. Its totient is φ = 54784000.

The previous prime is 138394219. The next prime is 138394259. The reversal of 138394240 is 42493831.

It can be written as a sum of positive squares in 4 ways, for example, as 136609344 + 1784896 = 11688^2 + 1336^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 138394196 and 138394205.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63570 + ... + 65710.

Almost surely, 2^138394240 is an apocalyptic number.

138394240 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 138394240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (167140260).

138394240 is an abundant number, since it is smaller than the sum of its proper divisors (195886280).

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

138394240 is a wasteful number, since it uses less digits than its factorization.

138394240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2261 (or 2249 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 138394240 is about 11764.1081259907. The cubic root of 138394240 is about 517.2565573763.

The spelling of 138394240 in words is "one hundred thirty-eight million, three hundred ninety-four thousand, two hundred forty".