138681438 has 32 divisors (see below), whose sum is σ = 318508800. Its totient is φ = 39432960.

The previous prime is 138681391. The next prime is 138681469. The reversal of 138681438 is 834186831.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 138681438.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1038 + ... + 16686.

It is an arithmetic number, because the mean of its divisors is an integer number (9953400).

Almost surely, 2^138681438 is an apocalyptic number.

138681438 is an abundant number, since it is smaller than the sum of its proper divisors (179827362).

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

138681438 is a wasteful number, since it uses less digits than its factorization.

138681438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15872.

The product of its digits is 110592, while the sum is 42.

The square root of 138681438 is about 11776.3083349579. The cubic root of 138681438 is about 517.6141165873.

The spelling of 138681438 in words is "one hundred thirty-eight million, six hundred eighty-one thousand, four hundred thirty-eight".