138775840 has 144 divisors (see below), whose sum is σ = 394377984. Its totient is φ = 45964800.

The previous prime is 138775787. The next prime is 138775841. The reversal of 138775840 is 48577831.

138775840 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (138775841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 242755 + ... + 243325.

It is an arithmetic number, because the mean of its divisors is an integer number (2738736).

Almost surely, 2^138775840 is an apocalyptic number.

138775840 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 138775840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197188992).

138775840 is an abundant number, since it is smaller than the sum of its proper divisors (255602144).

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

138775840 is a wasteful number, since it uses less digits than its factorization.

138775840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631 (or 616 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 43.

The square root of 138775840 is about 11780.3157852411. The cubic root of 138775840 is about 517.7315385133.

The spelling of 138775840 in words is "one hundred thirty-eight million, seven hundred seventy-five thousand, eight hundred forty".