138704640 has 144 divisors (see below), whose sum is σ = 454307616. Its totient is φ = 36044800.

The previous prime is 138704639. The next prime is 138704711. The reversal of 138704640 is 46407831.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157000 + ... + 157880.

It is an arithmetic number, because the mean of its divisors is an integer number (3154914).

Almost surely, 2^138704640 is an apocalyptic number.

138704640 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 138704640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (227153808).

138704640 is an abundant number, since it is smaller than the sum of its proper divisors (315602976).

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

138704640 is an equidigital number, since it uses as much as digits as its factorization.

138704640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 946 (or 932 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 33.

The square root of 138704640 is about 11777.2934072307. The cubic root of 138704640 is about 517.6429813323.

The spelling of 138704640 in words is "one hundred thirty-eight million, seven hundred four thousand, six hundred forty".