138405024 has 168 divisors, whose sum is σ = 433811700. Its totient is φ = 43296768.

The previous prime is 138404993. The next prime is 138405061. The reversal of 138405024 is 420504831.

It can be written as a sum of positive squares in 2 ways, for example, as 128595600 + 9809424 = 11340^2 + 3132^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 396402 + ... + 396750.

Almost surely, 2^138405024 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 138405024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (216905850).

138405024 is an abundant number, since it is smaller than the sum of its proper divisors (295406676).

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

138405024 is an equidigital number, since it uses as much as digits as its factorization.

138405024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394 (or 371 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 138405024 is about 11764.5664603503. The cubic root of 138405024 is about 517.2699923040.

Adding to 138405024 its reverse (420504831), we get a palindrome (558909855).

The spelling of 138405024 in words is "one hundred thirty-eight million, four hundred five thousand, twenty-four".