138308640 has 96 divisors (see below), whose sum is σ = 445870656. Its totient is φ = 36019200.

The previous prime is 138308629. The next prime is 138308689. The reversal of 138308640 is 46803831.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17290 + ... + 23990.

It is an arithmetic number, because the mean of its divisors is an integer number (4644486).

Almost surely, 2^138308640 is an apocalyptic number.

138308640 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 138308640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (222935328).

138308640 is an abundant number, since it is smaller than the sum of its proper divisors (307562016).

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

138308640 is a wasteful number, since it uses less digits than its factorization.

138308640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6762 (or 6754 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 138308640 is about 11760.4693783879. The cubic root of 138308640 is about 517.1498903810.

The spelling of 138308640 in words is "one hundred thirty-eight million, three hundred eight thousand, six hundred forty".