138615805440 has 1600 divisors, whose sum is σ = 609606518400. Its totient is φ = 29429858304.

The previous prime is 138615805387. The next prime is 138615805441. The reversal of 138615805440 is 44508516831.

138615805440 is a `hidden beast` number, since 1 + 3 + 8 + 61 + 580 + 5 + 4 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138615805441) by changing a digit.

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 159 ways as a sum of consecutive naturals, for example, 1557480916 + ... + 1557481004.

It is an arithmetic number, because the mean of its divisors is an integer number (381004074).

Almost surely, 2^138615805440 is an apocalyptic number.

138615805440 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 138615805440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (304803259200).

138615805440 is an abundant number, since it is smaller than the sum of its proper divisors (470990712960).

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

138615805440 is an equidigital number, since it uses as much as digits as its factorization.

138615805440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 172 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 45.

The spelling of 138615805440 in words is "one hundred thirty-eight billion, six hundred fifteen million, eight hundred five thousand, four hundred forty".