138289440 has 96 divisors (see below), whose sum is σ = 442846656. Its totient is φ = 36264960.

The previous prime is 138289439. The next prime is 138289447. The reversal of 138289440 is 44982831.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (138289447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26919 + ... + 31641.

It is an arithmetic number, because the mean of its divisors is an integer number (4612986).

Almost surely, 2^138289440 is an apocalyptic number.

138289440 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 138289440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221423328).

138289440 is an abundant number, since it is smaller than the sum of its proper divisors (304557216).

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

138289440 is a wasteful number, since it uses less digits than its factorization.

138289440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4802 (or 4794 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 138289440 is about 11759.6530561067. The cubic root of 138289440 is about 517.1259590310.

The spelling of 138289440 in words is "one hundred thirty-eight million, two hundred eighty-nine thousand, four hundred forty".