138618240 has 256 divisors, whose sum is σ = 478241280. Its totient is φ = 34062336.

The previous prime is 138618239. The next prime is 138618247. The reversal of 138618240 is 42816831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138618247) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1898844 + ... + 1898916.

It is an arithmetic number, because the mean of its divisors is an integer number (1868130).

Almost surely, 2^138618240 is an apocalyptic number.

138618240 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 138618240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239120640).

138618240 is an abundant number, since it is smaller than the sum of its proper divisors (339623040).

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

138618240 is a wasteful number, since it uses less digits than its factorization.

138618240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 138618240 is about 11773.6247604550. The cubic root of 138618240 is about 517.5354779756.

The spelling of 138618240 in words is "one hundred thirty-eight million, six hundred eighteen thousand, two hundred forty".