138740640 has 96 divisors (see below), whose sum is σ = 452148480. Its totient is φ = 35718144.

The previous prime is 138740629. The next prime is 138740647. The reversal of 138740640 is 46047831.

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 (138740647) 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, 8937 + ... + 18903.

It is an arithmetic number, because the mean of its divisors is an integer number (4709880).

Almost surely, 2^138740640 is an apocalyptic number.

138740640 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 138740640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (226074240).

138740640 is an abundant number, since it is smaller than the sum of its proper divisors (313407840).

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

138740640 is a wasteful number, since it uses less digits than its factorization.

138740640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10014 (or 10006 counting only the distinct ones).

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

The square root of 138740640 is about 11778.8216728160. The cubic root of 138740640 is about 517.6877612218.

The spelling of 138740640 in words is "one hundred thirty-eight million, seven hundred forty thousand, six hundred forty".