138639648 has 96 divisors (see below), whose sum is σ = 420166656. Its totient is φ = 39207168.

The previous prime is 138639643. The next prime is 138639659. The reversal of 138639648 is 846936831.

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

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a junction number, because it is equal to n+sod(n) for n = 138639597 and 138639606.

It is not an unprimeable number, because it can be changed into a prime (138639643) 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, 68215 + ... + 70217.

It is an arithmetic number, because the mean of its divisors is an integer number (4376736).

Almost surely, 2^138639648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138639648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (210083328).

138639648 is an abundant number, since it is smaller than the sum of its proper divisors (281527008).

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

138639648 is a wasteful number, since it uses less digits than its factorization.

138639648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2126 (or 2118 counting only the distinct ones).

The product of its digits is 746496, while the sum is 48.

The square root of 138639648 is about 11774.5338761244. The cubic root of 138639648 is about 517.5621190805.

The spelling of 138639648 in words is "one hundred thirty-eight million, six hundred thirty-nine thousand, six hundred forty-eight".