138501440 has 252 divisors, whose sum is σ = 427477428. Its totient is φ = 42577920.

The previous prime is 138501437. The next prime is 138501449. The reversal of 138501440 is 44105831.

It can be written as a sum of positive squares in 2 ways, for example, as 64128064 + 74373376 = 8008^2 + 8624^2 .

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138501449) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1897244 + ... + 1897316.

It is an arithmetic number, because the mean of its divisors is an integer number (1696339).

Almost surely, 2^138501440 is an apocalyptic number.

138501440 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 138501440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (213738714).

138501440 is an abundant number, since it is smaller than the sum of its proper divisors (288975988).

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

138501440 is a wasteful number, since it uses less digits than its factorization.

138501440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 138501440 is about 11768.6634755184. The cubic root of 138501440 is about 517.3900783282.

The spelling of 138501440 in words is "one hundred thirty-eight million, five hundred one thousand, four hundred forty".