138354640 has 20 divisors (see below), whose sum is σ = 321674724. Its totient is φ = 55341824.

The previous prime is 138354631. The next prime is 138354641. The reversal of 138354640 is 46453831.

It is a happy number.

138354640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 58859584 + 79495056 = 7672^2 + 8916^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 138354596 and 138354605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138354641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 864637 + ... + 864796.

Almost surely, 2^138354640 is an apocalyptic number.

138354640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138354640 is an abundant number, since it is smaller than the sum of its proper divisors (183320084).

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

138354640 is a wasteful number, since it uses less digits than its factorization.

138354640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1729446 (or 1729440 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 138354640 is about 11762.4249200579. The cubic root of 138354640 is about 517.2072168988.

The spelling of 138354640 in words is "one hundred thirty-eight million, three hundred fifty-four thousand, six hundred forty".